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Discuss Vaillant boiler not heating radiators. Please help! in the Boilers area at Plumbers Forums

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Sorry if this has been covered but I assume you've tried disconnecting a radiator and seeing if you get water out when heating is on? Is it warm?
 
Also are all you radiators the same
 
This is why noone want to take over from someone elses work
 
Exactly. I still reckon the problem lies with the rads or the TRVs
 
Did Vaillant charge for the two visits?
Has the heating zone valve been checked? whats on the pipe next to the zone valve for the heating?
 
Thanks Riley.

Looks like I'm left to consider options 1 and 4 then (as vaillant replaced the controls last week)

Also I thought you said that the valves weren't bi directional
 
Hi guys,

Just thought I'd follow up.

Vaillant came out today and replaced the pump in the boiler. They said it was fine but would do it for free as a precaution. Unfortunately the rads are still not getting hot!

That leaves 2 issues - rads piped wrong or poor circulation. I think it's the latter because some of the rads have been piped correctly and none of them are getting hot (even the ones piped correctly).

Now I'm trying to find out who's fault this is. The first plumber ran the pipe work but the second plumber commissioned the boiler. Is it correct to assume that the person commissioning the boiler should have checked the heating before confirming it was ok to put carpets down?

In terms of my options I really don't want to rip all carpets and floorboards up and digging out the chases. Is it worth doing a power flush first? How effective are they normally? I'm hoping that because the first rad in the circuit is not getting hot that the blockage is early on in the circuit.

What would you guys do in my situation please?

Thanks

If you're looking to blame, we don't know the full circumstance of your renovation.

Why did the first plumber not complete the job was there a falling out?
Yes the second plumber should've checked that the rads were heating up but was he working to your timescales was he under pressure to get done to a timescale?

It's difficult for us to comment
 
the photo of the radiator shows it piped up as normal radiator but instructions say should be top and bottom if all rads are the same this may be your problem
 
Sorry for the late reply guys. I will try and answer your questions below!

1. I haven't tried disconnecting a radiator but they are all filled up (I've bled them all)

2. Some radiators are warm, some are stone cold (so not all the same)

3. I've checked the specs of the valves and they ARE bi-directional (sorry I'm a novice when it comes to plumbing)

4. I'm not looking to blame anyone for anything. I'm just trying to understand if it's customary for a plumber to check that the rads were operating properly when commissioning the boiler as we only laid the carpets when he said he'd commissioned it.

5. The first plumber was my child hood friend. Unfortunately we fell out as he prioritised other jobs after I'd paid him in full up front and left me in difficult situations with other trades when he kept failing to show up. I wish we'd never fallen out!

6. Vaillant didn't charge for the first visit as they replaced the controls which were faulty. They did charge for the second visit as they said the boiler is working fine but there is poor circulation in the system.

I'm in a tricky spot as everything has been plastered and flooring laid. I ran out of money (was messed about a few times by various trades) so had to try and finish stuff myself and I can't afford to rip everything up and start again

How effective would a power flush be at removing a blockage? I have uponor pipes everywhere apart from copper coming out of the boiler.
 
It doesn't sound to me like a blockage. I'd say more likely a piping issue
 
It sounds like plumber no 2 comissioned the boiler not the heating system

I doubt a power flush will do any good

Why not use some of that money to pay no 2 or someone new to come back and look at the heating system
 
Thanks again guys.

I'm out of pocket twice now (paid plumber 1 in full and he walked off before it was complete and plumber 2 obviously needed to make it worth his while). I'm now way over budget without a properly working system!

So would the person commissioning the boiler not check that the radiators pumped out heat please? Plumber 2 fitted the towel rails and they're not getting hot either.
 
It's likely a piping problem. Drain and remove one non working rad turn on heating and open each valve into a bucket is the water hot?
 
So would the person commissioning the boiler not check that the radiators pumped out heat please? Plumber 2 fitted the towel rails and they're not getting hot either.

In theory yes, but only you and he know what you agreed/paid for
 
4 storey house and a system boiler? I don't reckon the pump is up to it. Needs a bigger pump
 
Unfortunately I know nothing about plumbing so thought commissioning the boiler entailed checking that it actually caused heat to come out of the radiators. There is a danger if you spell things out to the nth degree that the installer thinks you're an idiot whereas I'm quite easy going and try to be nice to people.

I've just turned off all of the rads apart from the stone cold one. It made a big gurgling sound near the boiler and now some heat is slowly going to it.

What is the sound likely to mean please? Should I keep running the heating? I don't want to push the blockage further along out of reach and under the tiles by keeping it running!

I've bled the rad and warm water is coming out but not hot.
 
Now you've bled it check it stays warm, the gurgling noise will be air.

If it stays warm, then slightly open the next furthest Rad from the boiler and see how that does.

May need balancing to get an even heat distribution.
 
Hi Riley,

Thanks for following up!

No update as of yet as the plumber hasn't been available. He is coming in to do a power flush on Thursday. I haven't got the skills to do what you suggested but bled the radiators and the water seems to be lukewarm even though the heating was on max for a couple of hours. What do you think that means please?

I obtained manufacturer instructions and some of the radiators (4 out of 12) can be piped either way and those aren't getting properly hot even with the others shut off so I'm not sure what the problem is.

I think it could be the pump not being up to the job (which is strange as the Vaillant engineer said it should be ok) or some sludge in the system.

I'm going to add some Sentinel x300 tonight and see if that improves things before the power flush is done on thursday. if that doesn't clear it up then will ask the plumber to fit a secondary pump.

If that doesn't work then I'm at a bit of a loss!
 
Have we definitely confirmed if valves are bidirectional
 
Hi guys,

A quick update.

I flushed the rads manually with a hose pipe a couple of weeks ago and when I drained a rad last night to add Sentinel X300 the water was clear.

However when I removed the bleed valve to dose the chemical loads of carp started coming out of the rad. This is a tiny rad! Now the pump in the boiler only seems to work on 'max' when there is a demand for hot water and doesn't seem to work as hard as when there is a demand for heating.

Is this normal in a system that is only a couple of months old? The original plumber did say that there was an unusually large amount of debris in the radiators given they were brand new.

image.jpg
 
No that's not normal but can happen needs to be flushed, chemicals in leave it as long as possible read the instructions and if you can take each rad off and flush with hose while beating gentle with a rubber mallet

aldo do you have a mag filter by the boiler ??
 
I would be getting onto the radiator company as well as I bet they weren't cheap Y
 
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