Radiator not working in new combi system!

[Andymitch58]

Hi, this is my first post 🙂 hope you can help.
About 2 months ago I had a worcester Bosch 24si combi boiler installed in a 13 year old 2bed house that I currently rent out. I got the local engineer off the WB website. He took out the bits of the old traditional system which were no longer needed and fitted the new boiler in the same position as the old one in the kitchen, useing the existing pipe work and radiators. All rads have thermo static valves apart from maybe one of them . I paid him a handsome sum and he told me it was all working and commissioned . However, within just a few days we realised the the bathroom radiator was not working. I then paid extra to have a new radiator installed at his suggestion. This did not solve it. He has now returned and put some 'strong chemical' into the system which he says is to try and break down a potential blockage. It has now been almost a week and still a very cold bathroom radiator and the new boiler is now making noises when hot! Please help! Any suggestions would be greatly received. Thanks Andy.

 

[wild nomad]

A few suggestions / questions:

* Did the engineer power flush the system before commissioning the boiler? This is definitely good practice. Otherwise it's like buying a brand new car and filling it with all the old oil and fluids from your old car.

* Although it doesn't sound like a large house, it's worth ringing up Worcester Bosch and telling them how many radiators you have. There is an outside chance that the expansion vessel in the combi isn't big enough for your heating system. This is unlikely though.

* I presume you have bled ALL the radiators? If not, start from the ground floor and work up. Also check that the pressure gauge on the boiler is reading at least 1 bar. As you bleed the radiators this will steadily go down so you need to re-pressurise every now and then as you bleed. Your Manufacturer Instructions should inform you what the ideal pressure reading should be. Normally between 1.0 and 1.2 bar.

* It could also be something simple like the radiators need balancing. Check with the engineer that they did this. Sometimes the radiators nearest the boiler and/or downstairs will 'steel' all the heat if the system isn't balanced correctly.

* Finally, blindingly obvious I know, but check that both the TRV and the lock shield is open. Sometimes the pin on the TRV gets stuck in the down position. This is easy to check by un-screwing the TRV head off and looking.

 

[steadyon]

Is it possible that the bathroom radiator was run of the hot water primary circuit? The combi has no primary hot water circuit, and it may be that the installer missed this. Try checking the pipework attached to the bathroom radiator as far as possible back towards the boiler.

 

[Andymitch58]

Is it possible that the bathroom radiator was run of the hot water primary circuit? The combi has no primary hot water circuit, and it may be that the installer missed this. Try checking the pipework attached to the bathroom radiator as far as possible back towards the boiler.

Many thanks to Wild Nomad and Steadyon for your excellent advice! I think steadyon has hit the nail on the head! We now know that the bathroom radiator did come hot when the hot water in the bathroom was on. I have not spoken to the engineer yet but clearly he was not familiar with this 'peculiarity' and I assume he has capped off the bathroom radiator pipe somewhere. Question now is:
1. Is it a straightforward job to connect the bathroom radiator pipe work up to the new system ?
2.should I expect the engineer to complete this work at no extra cost? (Keeping in mind that he has already charged me to replace the bathroom radiator which clearly didn't need replacing) . Your thoughts would be most welcome. Thanks, Andy .

 

[wild nomad]

Hi Andy,

Strictly speaking I wouldn't say it's the plumbers fault. If you didn't mention that the radiator got hot when the hot water was used then there is no reason to suspect that the radiator was hooked up to the hot water pipes. Who ever put in the system originally is to blame there.

It may also be to your benefit that you have a new radiator because if the old one was running off the water supply then it would have been rusting from the inside out contaminating your water supply since there is no inhibitor in your water supply. Of course this means that the same will be happening to your new radiator so it is best to get it fixed ASAP. Remember this is water that you could potentially be drinking. To be safe only drink out of outlets directly joined to the mains supply. This would normally be the kitchen sink.

It is impossible to tell if it's a big job without being able to look at the system. It all depends on where the radiator pipes meet the water pipes and how accessible they are.

By the way, does the new radiator still warm up when you use the hot water in the bathroom for any length of time?

Hope this helps buddy!

 

[steadyon]

If the radiator was previously on the hot water circuit it would almost certainly have been on the primary, i.e. the same circuit as the coil in the hot water tank. This would not have suffered from rust or corrosion problems more than any other radiator. You may very occasionally come across a bathroom towel rail / radiator run off the actual hot water circuit, but if so its likely to be a big bore radiator in copper or brass with a chrome finish. You often get these in blocks of flats with community heating / hot water.

In my opinion the installer should have checked which circuit the bathroom radiator was on, as it is / was quite common to have them on the hot water primary to get warm towels during the summer when the central heating is off.

There is no telling how complicated it would be to add it to the general heating circuit. It could be just two pipe connections in the old airing cupboard. It could mean digging up floors and tracing /re-running pipes. Probably a good case for compromise - get an estimate for the cost then offer to pay half or two thirds, so the plumber isn't working for nothing but neither is he making a normal profit. Had he identified the issue before quoting he would have had the opportunity to add the cost to his quotation so you would have paid for it anyway.

 

[stevetheplumber]

wild nomad you are talking out of your nether regions rads that are discribed as running on the hot water still have heating system water in them but they are run from the primary circuit
if you ran fresh water through a steel rad it wouldnt last 3 months
sounds like when the cylinder was removed he has cut the circulation to this rad depending on the layout it could be easy or difficult to re pipe

 

[village idiot]

Hi Andy,

Strictly speaking I wouldn't say it's the plumbers fault. If you didn't mention that the radiator got hot when the hot water was used then there is no reason to suspect that the radiator was hooked up to the hot water pipes. Who ever put in the system originally is to blame there.

Hope this helps buddy!

REALLY?
Ofcourse it is the plumbers fault. Who is the expert here? The OP or the Engineer? There was no need to change the bathroom rad. Waste of money. Get the idiot back to sort it. And no power flush needed. He could even have left the chemical in there too long, hence the now banging noises?

 

[kay-jay]

It was common to have a landing or bathroom rad off the hw. He should have checked fjrst. And when it didnt heat up he definitely should have realised it was possible and checked before replacing rad. He should sort it without charging. Shouldnt be a hard thing to connect up assuming your floor isnt tiled

 

[Ermintrude]

WB SI? Tool of choice for inexperienced muppet. Sounds like he's got limited experience and understanding . Even apprentices understand bathrooms on primaries, that's what we check when stripping out. Bung pf and put wet vac on pr. Open bleed on rad and your off!