Remeha - one radiator since service

[chriselevate]

I have a Remeha Avanta Plus 39C boiler and since it was serviced (4 months ago) it is only powering one radiator (a towel rail in my en suite) now I've switched the central heating on tonight.

I'm wondering if the plumber accidentally changed a setting on the console as he was reducing the temperature of my tap water.

Could this be the case? If so, is there a procedure on the console (R, -, + and Enter key) to switch the rest of the radiators back on?

Thanks

 

[chriselevate]

Could anyone help with this please?
I just can't seem to get more than one radiator working and don't know why this is the case.
Thanks

 

[Echo the husky]

Are the other radiators on a different zone to the towel rail?

 

[ianmcd]

unlikely to be the boiler if one radiator is working, what external controls do you have ?

 

[chriselevate]

Ok..... so I've done a diagram of the problem to give you and idea of what I've got.



Towel rail is upstairs in RED and I can get it HOT.
The downstairs RED one I can also get HOT.

But the BLUE one downstairs I can't get hot and many others I can get hot(ish) but the return 22mm pipe at the boilers is only ever luke warm.

Here is a shot of the boiler....



I've added (F)low and (R)eturn and (T)owel to show where I guess they've come off the 22mm's into 15mm's in order to go upstairs to the Towel Radiator.
Also worth noting...
1. The Flow is ALWAYS extremely HOT - even when the return is luke warm.
2. When running the heating system the hot water seems to raise a LOT in temperature.
3. There are no fault codes on the boiler.
4. The pressure is fine.

 

[ianmcd]

As already said I dont think the problem is with the boiler

 

[chriselevate]

I have hive fitted and it only has on and off. As far as I'm aware there are no external controls on the system.

 

[ianmcd]

in your pic the hive is calling for heat, the boiler can not decide which rads to heat so it is either on or off, your problem is not with the boiler

 

[chriselevate]

So, surely Hive is simply saying ON or OFF. So therefore, I don't know why it's only running one or two random radiators? For example.... if I switch the CH on (via hive) and have the Towel Radiator on - it comes on and I get Flow and Return on the boiler REALLY hot.

If I switch off ALL radiators and try the one near it downstairs (in red on the diagram) I get a HOT radiator and both Flow and Return on the boiler are REALLY hot.

If I switch off ALL radiators and try the on furthers away downstairs (in blue on the diagram) I get a cold radiator. The Flow is REALLY hot and the return is slightly luke warm.

I agree it's probably not the boiler but I don't know what else to do in this case.

 

[ianmcd]

you are way over thinking this, the more radiators that are switched on, the cooler the return pipe will be , just switch on the radiators that you want to heat up and let the boiler do its job, you might need your system balanced but has nothing to do with the boiler

 

[chriselevate]

Hi Ian, this is what I'm trying to explain. If I only have 1 radiator on out of 15 then surely the Flow and Return 22mm pipes on the boiler should both be REALLY hot. If I put all 15 radiators on then I should feel the Flow as REALLY hot and the Return less hot. This is the way it works surely?

So.... my point is... that even if I only switch on 1 radiator (the blue one in the diagram) I get a REALLY hot Flow but I get a slightly warmer that cold (but not even warm) Return. This can't be right surely?

And in answer to your question.... "just switch on the radiators that you want to heat up and let the boiler do its job, you might need your system balanced but has nothing to do with the boiler" This is how I started and how I've been trying it and it isn't working.

 

[terryplumb]

chriselevate ,you stated that you had a service on your boiler 4 months ago ,so was your central heating working fine before this service ? have you since then only been using it for domestic hot water ,then weather gets colder ,you put c/ heating on and find the problems with rads ? have all the lockshield valves on all radiators been left untouched ? if the answers to all questions above is YES ,then it would appear to be a circulation problem. if you have altered the lockshield valves then you have unbalanced the system. are the other valves trv or wheel head ? it is only those that you should use to turn a radiator off ,not the lockshields.

 

[chriselevate]

Hi terryplumb. Yes, CH was working fine before the service 4 months ago. Yes, just been using domestic HW until I tried the CH a few weeks ago. At that point, I just switched it on and noticed that only one radiator (the towel tail) was blazing hot and all the other radiators we cold. I contacted the plumber who did the service and told him and he advised me to switch off all the TRV's bar one and see if I could heat to the furthest radiator. All the lockshield valves were untouched. I agree it looks like there is a circulation issue somewhere. The reason I'm thinking this is, the boiler sounds fine (as previous commented by ianmcd) as it's able to provide heat for domestic HW and CH and it would show a fault code if not. I am also thinking that there isn't a pump issue as the boiler would show a fault code for this too.

 

[ianmcd]

just for information, in your pic you have marked the flow and return the wrong way round the flow is the pipe in the left hand side of your pic, not that this will make any difference to your problem, did you do as your plumber suggested and try closing down all the radiators and only open one at a time and see if you can get that one hot then close it and do the same with the next one , do them all one at a time to see if you have a blockage somewhere.

 

[chriselevate]

Good spot with the flow and return. I labelled them from memory while I was at work and got them wrong. Good spot! Thanks.
So the advice you would give is the same as what the plumber said... Isolate ALL rads except one and check that I can get each one in turn REALLY hot and therefore the Flow and Return will be nice and hot too? You're thinking it might be something like an air block somewhere? Are there any other tips to getting it back up and running or where to vent/try first etc?

Interestingly, the one I've highlighted in blue on the downstairs diagram is the only radiator I have where there's a drop from upstairs to reach this one. It drops for this one radiator and is always the one that's last to get warm when the CH comes on. I guess this would indicate something?

Thanks again for all the advice and feedback on here. I hope to be able to resolve it myself if possible. The plumber is saying he's too busy to come and take a look - which is not ideal so I guess I'll be looking for a new person to service my boiler next year?!?