Vaillant boiler not heating radiators. Please help!

[Riley]

The weather compensation is built into the V smart controller mate you connect it to the Internet add your postcode and it takes weather updates from the Internet

 

[Riley]

Internal bypass isn't it

 

[ShaunCorbs]

The weather compensation is built into the V smart controller mate you connect it to the Internet add your postcode and it takes weather updates from the Internet

Will the boiler work without it for a test ?? Not good with vailliants

 

[ShaunCorbs]

Internal bypass isn't it

Unless it's a system boiler always stick one in

 

[Riley]

I would've said just disconnecting from the Internet will do it as you have a separate wireless thermostat as well

 

[Riley]

I'm leaning more and more to the radiators been piped wrong

 

[ShaunCorbs]

I'm leaning more and more to the radiators been piped wrong

What's getting me is the flow temp sticking at 35 if rads / Pipework were wrong would just short and over temp would think ??

 

[Riley]

I think the OP Did say that some of the radiators get Warmish???

 

[jonnyswamp]

Ah give me a slap, I didn't read the 35 degree bit

 

[ShaunCorbs]

Ah give me a slap, I didn't read the 35 degree bit

It's a Friday

 

[Gasmk1]

sounds like the weather comp also its summer so it would run very low temp the only way to be sure is to remove the weather comp and run as normal boiler. as for rads fitted wrong some manufacturers put a small dimple in the header to let you know thats the bottom/top.

 

[Rystar00]

Thanks very much again guys. Will upload a pic of the install when I get home in half an hour.

To answer some of the questions:

1. I'm not sure if a bypass valve was fitted. It's an invented cylinder system. Will you be able to tell by the picture I will upload?

2. I turned the Internet off so it couldn't take data from the weather (put comfort override on which makes it operate according to the room stat). I put the room stat in the fridge to trick it into thinking it was cold. The flow temp reaches 75 degrees very briefly (less than 1 minute) and goes back down to 35 even though I'm asking for 30 degrees from the rads.

3. I have got the instructions for the radiators here. Will upload them and a pic of the rads. Silly question but is it possible to hang rads upside down (ie the flow and returns go where the air vent and blanking plug should be) as well as the flow and returns being in the wrong hole?

 

[ShaunCorbs]

Your rad instructions should tell you which way is best / any no nos

 

[Riley]

Thanks very much again guys. Will upload a pic of the install when I get home in half an hour.

To answer some of the questions:

1. I'm not sure if a bypass valve was fitted. It's an invented cylinder system. Will you be able to tell by the picture I will upload?

2. I turned the Internet off so it couldn't take data from the weather (put comfort override on which makes it operate according to the room stat). I put the room stat in the fridge to trick it into thinking it was cold. The flow temp reaches 75 degrees very briefly (less than 1 minute) and goes back down to 35 even though I'm asking for 30 degrees from the rads.

3. I have got the instructions for the radiators here. Will upload them and a pic of the rads. Silly question but is it possible to hang rads upside down (ie the flow and returns go where the air vent and blanking plug should be) as well as the flow and returns being in the wrong hole?

As far as I'm aware this boiler has an internal bypass

Has the heating ever worked? Do you get any errors at the boiler?

Yes it's possible but unlikely. Usually if manufacturers specify a way to pipe the rad they will add stickers or some sort of indicator

 

[quality]

does the vailliant system have a base setting for heat demand ?

 

[Rystar00]

Hi guys. Looks like the boiler is now firing up to full temp.

Have attached some pics to this post.

Some of the radiators (not all) are warming up but the heating has been running for 2 hours and I would expect them to be almost too hot to touch. Some are still stone cold (valves are open) and some which were previously hot are now cold! I'm so confused!

 

[Riley]

When was it installed???

 

[Rystar00]

Double post

It was fitted by the first plumber in September 2015 but not commissioned until 2 months ago. It was a long renovation,

Hot water been fine but heating always lukewarm

 

[ShaunCorbs]

by the looks of it rads installed wrong well going off instructions thats is

do a test

get the installer to turn hot water on (heat the cylinder) and manually open the two port to the rads (heating circuit) not via the head

does the heating work then?

 

[Stoney Ground]

First thing I would do would disconnect all controls and link out boiler to run totally independent, manually open heating zone valve.

Close all lock shield valves except furthest rad, check it heats up and identify F&R and if rad is piped as per instructions.

You could have 4 problems causing same effect
1. Rads piped wrong (shows top/bottom same end)
2. TRVs on return
3. Controls
4. Pump not man enough.

Solve each one in order, don't try to solve all at once.

Then repeat for next nearest rad, closing previous ones

 

[Rystar00]

Thanks very much guys. It's very kind of you to help

I have a vaillant engineer coming out on Saturday to rule out anything with the boiler. If it isn't the boiler I will show this thread to my installer.

Out of interest would it matter if the TRVs were on the returns if they're bi-directional please?

 

[Riley]

No if they are bidirectional that's what they're designed to do so it doesn't matter which pipe they are on

 

[Rystar00]

Thanks Riley.

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

 

[Riley]

Thank you for coming back please keep us posted

 

[Rystar00]

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