Any heating engineers - need input on DCH closed system water pressure and radiator performance

jondc

jondc

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Jon
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Hoping for a bit of advice, as I feel I am being fobbed off.

I have had 5 new radiators fitted to replace existing standard ones, three of which are none standard design, classed as 'designer radiators'. These were purchased to fit in with a new kitchen and was a fair price each. I am struggling with them, all designer radiators take ages to warm up, far longer than the towel rail or the other standard radiators, with one never getting up to temp even when all flow directed to it and left for an hour. I purchased an infrared thermometer to try and work out what is happening.

The worst, when tested after an hour of calling for heat, had a flow pipe water temp reading of 56°C but the bottom of the 1st bar was only 39.6°c the 2nd to 5th was 50°C (give or take) and the 6th-9th bars dropped to 40°C. Another again takes over an hour to warm up, even when full flow directed to it. This one was reading 57°C in on the flow pipe but 44.9°C on the 3rd tube.

I have bleed and balance the system. All non designer radiators now have return valves only partially open, to limit flow whilst still providing heat, the three designer rads have flow and return valves at nearly full open. Even with TRV heads removed, there has been no change in performance.

After multiple discussions with the suppliers, and providing evidence of the hot water flow up to and through the radiators, they have suddenly said my boiler pressure is too low. Surprisingly and suddenly, after I had told them my system pressure is two bars, these radiators need 3 bars to operate and they have asked me to 'try changing my boiler' (This was after asking me to swap radiators around). This system pressure information was not on the sales information or in the installation instructions. This sounds a bit 'too convenient' for me but I am not a heating systems engineer.

I can under stand a low pressure, say less than 0.5 bar, could affect the system performance but as the boiler is meant to work in this the pressure range, as it is set, is a 2 bar pressure and flow thats was suffice for the same quantity or radiators really the issue?

or am I being fobbed off and its a bunch of badly built radiators with poor through flow?

If interested, here are the videos of what I sent re hot water flow, which I sent along with the system pressure info and the fact I have balanced and bleed the system, to which I got the change your boiler response.
photos.app.goo.gl

Radiators

5 new photos added to shared album
photos.app.goo.gl photos.app.goo.gl

Thanks in advance
Jon
 
Yep ,you are being fobbed off, in 30 odd yrs as a heating engineer I have never had to run a sealed system at 3 bar for the rads operate correctly, if you have the original manufacturers installation instructions see if it mentions it in there, I doubt very much if it does. In my time I have fitted dozens of 'designer' rads over the years. Yes, some of them do take a little longer to heat up, but not an hour. I have fitted some that are flow/return specific, it would be worth while checking to see if yours are. It may be worth taking one of the rads off the wall (the worst performing) and just make sure there are no restrictions within the rad where the valve tail is (I've had excess ptfe tape cause problems before now) have a good look inside the rad if you can but try not to poke anything in as if there is something inside the rad you may just push it in even further making matters worse. Whilst the rad is off run each of the valves into a bucket (or a heavy duty rubble bag)to make sure you have good flow out of them.
Just looked at the photos,also try taking the head off the thermostatic valve (just unscrew the knurled nut under the thermostat head) and run it without it fitted.
 
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mex said:
Yep ,you are being fobbed off.
Just looked at the photos, also try taking the head off the thermostatic valve (just unscrew the knurled nut under the thermostat head) and run it without it fitted.
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Yes, there was no mention of system pressures in the sales literature or the installation instructions.

The installation instructions say they can only go one way up to ensure the water is correctly distributed throughout the radiator by the distributor block, it does not say anything about flow or return.

I have ran the system with the TRV heads off and with all other rads but one closed down, with no change.

I feel it is the flow through the rads, as some of the upright pipes get hot, whilst others don't and its only these three rads that I am having issues with.

Can I ask, what is a distributor block and how do these work?

Thank you
 
mex said:
Yep ,you are being fobbed off
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I was going to respond to them

'Come on, please be serious, change the boiler!. A 3 bar system requirement was not mentioned in the sales literature, nor is it mentioned in the installation guide or troubleshooting section therein. A 3 bar system requirement would also preclude these radiators for use by most UK central heating systems.

The radiators have been fitted in line with the supplied installation guide, the system has been bleed and balanced. The boiler is operating within the recommended pressure guidelines, which is designed to replicate the head pressure that an open-vented system would run at in order to maintain prime at all the points in the system. One bar is about 33 feet of water head. A 3 bar pressure is equivalent to running at over 100 feet of water head, which is equivalent to having a head tank in the loft of in one hell of a tall house! It's way too high.

Please provide a serious resolution to this issue'

Is what I am saying correct?

Thanks for your input.
 
Just out of curiosity when they fitted the new rads did they drain down the whole system or use a pipe freezer and isolating valves?
And yes you are being fobbed off, pressure has bugger all to do with flow rate which is what determines now quick the system heats up.
 
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jondc said:
Yes, there was no mention of system pressures in the sales literature or the installation instructions.

The installation instructions say they can only go one way up to ensure the water is correctly distributed throughout the radiator by the distributor block, it does not say anything about flow or return.

I have ran the system with the TRV heads off and with all other rads but one closed down, with no change.

I feel it is the flow through the rads, as some of the upright pipes get hot, whilst others don't and its only these three rads that I am having issues with.

Can I ask, what is a distributor block and how do these work?

Thank you
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I'm guessing the block is something the manufacturer has put inside the rad, it will probably just be a baffle to stop the water flow going straight across the bottom of the rad from flow to return. It may be worth contacting them again and asking if the rad is flow directionaly specific. IMO it's most likely the return is the problem not the flow, which makes me think its fitted arse about face.?
 
might be worth checking around the valve connections on the rad itself to see if there is a directional arrow somewhere, I've seen this but it will usually be quite a subtle mark and sometimes even on the reverse of the rad so get a small mirror and have a look.
 
I take it that the "out" side valves are all fully open.
 
Just a stab in the dark, also check the valves at the boiler flow and return are open (the far left 22mm pipe and far right 22mm pipe under the boiler).
 
mex said:
I'm guessing the block is something the manufacturer has put inside the rad, it will probably just be a baffle to stop the water flow going straight across the bottom of the rad from flow to return. It may be worth contacting them again and asking if the rad is flow directionaly specific. IMO it's most likely the return is the problem not the flow, which makes me think its fitted arse about face.?
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Flossyrockstar said:
Just out of curiosity when they fitted the new rads did they drain down the whole system or use a pipe freezer and isolating valves?
And yes you are being fobbed off, pressure has bugger all to do with flow rate which is what determines now quick the system heats up.
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System was drained down and flushed, as also had new boiler and 3 way valve.
Thank you.
 
mex said:
get the installer back to check.
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Really appreciate your help on this.
I have tried to get installer back, he is meant to be coming tomorrow, but what should I ask him to check?
 
jondc said:
Really appreciate your help on this.
I have tried to get installer back, he is meant to be coming tomorrow, but what should I ask him to check?
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Just tell him what you have told us. If he's worth his beans he'll get to the bottom of it for you.
 
mex said:
Just tell him what you have told us. If he's worth his beans he'll get to the bottom of it for you.
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Thank you, I will see what he says.
 
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Just noted that on two of the radiators, the flow is on the wrong side according to the datasheet. Considering the one that is fitted with the flow as directed, and all take ages to warm up, will it make much difference to the performance considering its only a block placement, to stop water flow from just going along the bottom rail, not a one way valve?

Thank you
 
The answer is get the rads installed as per manufacturers spec and see what happens...such a mistake does leave me with concerns over the original installer though...if he has got that wrong, what else????
 
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Pete E said:
The answer is get the rads installed as per manufacturers spec and see what happens...such a mistake does leave me with concerns over the original installer though...if he has got that wrong, what else????
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Thank you. I do fear this will be an issue........ The alteration connections where made whilst my kitchen ceiling was removed and they may fall under my tiled bathroom floor! even if they agree to do it.
 
jondc said:
Thank you. I do fear this will be an issue........ The alteration connections where made whilst my kitchen ceiling was removed and they may fall under my tiled bathroom floor! even if they agree to do it.
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That sounds like a nightmare...I installed my own solid fuel heating system in the past, and that sort of thing was my biggest fear..is there no way things can be reversed at the individual rads, even if only on a temporary basis to see if it cures the problem?
 
Pete E said:
That sounds like a nightmare...I installed my own solid fuel heating system in the past, and that sort of thing was my biggest fear..is there no way things can be reversed at the individual rads, even if only on a temporary basis to see if it cures the problem?
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I will ask them and see, just annoyed that on a costly kitchen refresh constant errors that have been made are coming to light and the finish is now being unfinished! A big lesson learnt..... do not supply any items yourself as this equal a big get out clause by either side...........
 
jondc said:
Just noted that on two of the radiators, the flow is on the wrong side according to the datasheet. Considering the one that is fitted with the flow as directed, and all take ages to warm up, will it make much difference to the performance considering its only a block placement, to stop water flow from just going along the bottom rail, not a one way valve?

Thank you
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Going to make all the difference, if it made no difference the manufacturer would not have made them directional specific.
 
mex said:
Going to make all the difference, if it made no difference the manufacturer would not have made them directional specific.
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The nightmare continues....

:(

Thank you all for the input.
 
I'm not a heating engineer... but if they are all the wrong way, could you not just swap them at the boiler?
 
I know nothing about this, but can you buy new radiators to install with the flow the other way round?
 
J Veitch said:
I'm not a heating engineer... but if they are all the wrong way, could you not just swap them at the boiler?
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Not sure thats an options, as in my mind then the current correct wrongs would be incorrect.
 
tijuana taxi said:
I know nothing about this, but can you buy new radiators to install with the flow the other way round?
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It may be an option but, considering;

a)one is right and still takes ages to warm up
b) I have paid a professional to fit them and they was made available before pipework installed,

I am reluctant to spend another few hundred pounds.
 
Was due to have flow changed this Friday, but now who knows.
 
Flossyrockstar said:
Any news, did they get to the root cause?
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They corrected the flow and return, which has made an improvement but still takes a while for them to warm up, particularly the tall single one. I have fitted wiser trv controls and so have scheduled that these come on before the others. This gives them max flow and a lead in time. The radiator suppliers are not wanting to make life easy in Changing them.
 
Bobsyeruncle said:
What's the heat output of the boiler?
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I don't know. It's a new boiler so hopefully enough. They all get hot, and the normal ones in minutes. It's only the designer ones that take a while. Personally I think that have too much resistance against the flow compared to the normal ones.
 
The designer radiator I have had these control screws on the bottom that had to be put in to select the desired flow pattern, anything like that on yours? Put in wrong they would basically restrict flow.
 
robj20 said:
The designer radiator I have had these control screws on the bottom that had to be put in to select the desired flow pattern, anything like that on yours? Put in wrong they would basically restrict flow.
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Yes they have fixed blockers in, hence them being flow specific. Two of three where fitted incorrectly but now all sorted with regards to flow direction. Still crap at getting hot, all show........ I would just swap them but kitchen had been refitted around them, so pipework plastered in the wall specifically for these.
 
jondc said:
Yes they have fixed blockers in, hence them being flow specific. Two of three where fitted incorrectly but now all sorted with regards to flow direction. Still crap at getting hot, all show........ I would just swap them but kitchen had been refitted around them, so pipework plastered in the wall specifically for these.
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I was toying with the idea of fitting designer rads earlier in the year (glad I didn’t now with the trouble you have had) as I’m upgrading our heating system a chunk at a time as we have a mixture of microbore and standard pipe work. Started with the boiler last November and in the summer I decided to go with smiths skirting radiators in the lounge, dining room and one of the bedrooms to trial them out. So far they’re doing really well although we’ve only had three days of sub zero temperatures they heat up really quick and apply an even warmth across the room and they free up a section of wall where there would be a radiator.
 
Flossyrockstar said:
I was toying with the idea of fitting designer rads earlier in the year (glad I didn’t now with the trouble you have had) as I’m upgrading our heating system a chunk at a time as we have a mixture of microbore and standard pipe work. Started with the boiler last November and in the summer I decided to go with smiths skirting radiators in the lounge, dining room and one of the bedrooms to trial them out. So far they’re doing really well although we’ve only had three days of sub zero temperatures they heat up really quick and apply an even warmth across the room and they free up a section of wall where there would be a radiator.
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Yes, over priced and under performing....... But traditional radiators don't look so great stuck on a wall in an open kitchen/dinner. I did have kick space heaters in the past, they was really good but it was for a lot smaller area than this time.

My mum is upgrading her system, I have started to consider some skirting radiators for her. Good to hear some feedback on them, do you have some photos of what they look like fitted?

Thanks
 
jondc said:
Yes, over priced and under performing....... But traditional radiators don't look so great stuck on a wall in an open kitchen/dinner. I did have kick space heaters in the past, they was really good but it was for a lot smaller area than this time.

My mum is upgrading her system, I have started to consider some skirting radiators for her. Good to hear some feedback on them, do you have some photos of what they look like fitted?

Thanks
Click to expand...
Skirting radiators provide a low level of heat, so are designed to be used in highly insulated properties, such as new builds etc.
You may find they're not warm enough compared to standard radiators if you're in an older property.
 
jondc said:
Yes, over priced and under performing....... But traditional radiators don't look so great stuck on a wall in an open kitchen/dinner. I did have kick space heaters in the past, they was really good but it was for a lot smaller area than this time.

My mum is upgrading her system, I have started to consider some skirting radiators for her. Good to hear some feedback on them, do you have some photos of what they look like fitted?

Thanks
Click to expand...
These are the ones I’ve fitted.
www.radiators.co.uk

Smiths Sureline 1000 Hydronic Perimeter Fan Convector

Shop Smiths Sureline 1000 Hydronic Perimeter Fan Convector MPN: HPSL30002
www.radiators.co.uk www.radiators.co.uk
 
Bobsyeruncle said:
Skirting radiators provide a low level of heat, so are designed to be used in highly insulated properties, such as new builds etc.
You may find they're not warm enough compared to standard radiators if you're in an older property.
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The house was built in 1969 from a crosswall construction so not the most energy efficient. So I’ve gone on BTU,s required for the rooms and added approximately 25-30% by running across the entire length of wall in each room with the skirting rads.
The one room I was quite concerned about was the bedroom as it was always colder than the rest of the house, it now seems the same as all the rest but as I said I’m only going on three days of cold weather that we have had so far this autumn and some of the gains could be down to the crappy micro bore being replaced. I’ll keep you informed about the performance of them as the winter progresses if your interested.
 
jondc said:
Yes they have fixed blockers in, hence them being flow specific. Two of three where fitted incorrectly but now all sorted with regards to flow direction. Still crap at getting hot, all show........ I would just swap them but kitchen had been refitted around them, so pipework plastered in the wall specifically for these.
Click to expand...

Did you get a 2nd opinion regarding the rad/s installation/s? it would be helpful if you could get some decent photos of the rad valves too.
 
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