rayburn central heating not heating

[lewisplumber]

Hello all. I am on a job where the heating is not getting hot. The pump works the 3 port is capped on one side so i am assuming it is directed to heating only. There heating has not been on since last year. I drained hot off the cylinder so that the water would be demanded to the coil to heat the water and nothing. which would have brought heat through the central heating system. The Rayburn was serviced this year. Looking over the system the Ray is firing up but nothing is going through the flow and return heat wise. The system has been at least 12 years without power flushing. Any suggestions??

 

[oilman]

the A port on the mid position valve should go to the radiators and B should go to the the water heating coil
have you investigated whether the valve is being opened ?

 

[dontknowitall]

I'm sure you've probably done this but if you have access to the primary flow and return up the wall behind the Rayburn (usually) you can feel the pipes and get some quick knowledge. For example, if they're both cold then the problem rests within the Rayburn and if both hot then the problem is in the airing cupboard. Probably teaching you to suck eggs but sometimes these simple things are forgotten if you don't come across them regularly!!

Is there a pump and are the pipes equal warm/hot temperatures everywhere?

 

[lewisplumber]

Cheers for the help. Like you are saying if your not on it day in day out you get a bit forgetful. The pipes are barely warm at the Ray and the Ray is red hot. So i am guessing its the Ray but it has only been worked on in the last few weeks. But the customer has only just put on her heating. I am going back tomorrow and will let you know the score. Cheers people.

 

[dontknowitall]

If you're still reading and if it's of any help - presumably you know these have two burners? One for the cooker and one for the heating and hot water. The pipes can warm a little just from the cooker, just as the cooker can warm a little when only the heating/hot water is on.

 

[lewisplumber]

Yes as you look in the door there are 2 chambers. The bigger one is for the central heating. It fires up and thats it for a short while.

 

[dontknowitall]

Good luck when you go there. I took one out earlier this year. It really bothered me not finding the problem. Radiators would warm up well for about an hour then the whole system would shut down for many hours. In the cold weather this wasn't funny. I changed one or two TRVs, sorted out the clash of a room stat and TRV, fitted larger rads to one room where they were undersized and all sorts.

Then I found a wiring fault. Sorted this out eventually.

Still had a problem. I was about the 4th plumber on the scene.

I worked with another plumber. Still no luck.

We took the machine out and replaced it with a different system in the end. Turned out that the electrician had come across one where Rayburns (480Kb) can develop a "fault" where the heat shield deforms and the heat from the cooker seeps into the heating/hot water area and triggers the high limit thermostat. When the cooker was off, the heating worked wonderfully but when the cooker was on (as it needed to be to help warm the room) then the heating turned off. Maddening!!

I'm not saying this one has that fault, but you have to have your wits about you with these things!!! Best of luck.

 

[lewisplumber]

Great stuff going to sleep well tonight. The pump was full of air as well. I flipped it round and it stopped. Now i am thinking that was wrong and there is something to do with the Rayburn.

 

[lewisplumber]

Blockage. Needs powerflush.. Bet they dont do it before christmas!