Would appreciate if anyone could shed any light on the following overheating boiler problem.
The system consists of a Baxi solo 50 bolier (installed late last year) utilising an indirect cylinder with a 2-way zone valve installed in the heating circuit, prior to today there was no tank stat or room stat fitted resulting in the boiler cycling a lot and also very hot tap water besides this howver it appeared to work OK all radiators (7) warming up quickly and no overheats, since having the new boiler installed we have always had the controller set for both heating and water. There is a old manual thermostatic valve with a capillary tube attached to side on tank fitted in the hot water circuit but opening or closing this made bugger all differnce to the hot water tempreature.
Today using my humble DIY knowledge and several hours research on the Internet I fitted a tank stat and a wireless room stat (drayton RF3) . Powered everything back on set controller for heating and water and all seemed fine, both the room stat and cylinder stat working OK. Room came up to tempreature in around 30 mins and the room stat shut off the 2 way valve in the heating cirucit, within 2 minutes of this happening banging noises from the boiler and it shut down with overheat light. Let everything cool down and tried again exactly the same as soon as the heating valve shut down overheat in less than 2 minutes. Tried with just water and no heating and again shut down in under 2 mins.
The hot water is warming up, and there is a manual bypass valve fitted in the flow and return of the boiler.
Didn't have this issue on old boiler, there again it was 25 years old with a corroded heat exchanger and probably not giving out as much heat as the new one.
To me it seems like the hot water circuit can't take the heat away quick enough and hence the overheat, I'm a total novice at heating systems but the hot water cylinder itself looks a bit odd, all the indirect cylinders I've seen have the feed for the coil entering on the side of the tank this one (looks really old) has the feed entering and exiting via 15mm pipes via what looks like an immersion plug in the top of the tank, the pipe is reduced down to 15mm from the 22mm feed from the pump.
You can see a picture of the top of the tank at
http://www.mjspc.demon.co.uk/hwc.jpg
Is this just an old tank or has somebody bodged together some sort of indirect cylinder, seems strange it should only have a 15mm feed to the coil.
Any help or advice much appreciated.
Cheers.
The system consists of a Baxi solo 50 bolier (installed late last year) utilising an indirect cylinder with a 2-way zone valve installed in the heating circuit, prior to today there was no tank stat or room stat fitted resulting in the boiler cycling a lot and also very hot tap water besides this howver it appeared to work OK all radiators (7) warming up quickly and no overheats, since having the new boiler installed we have always had the controller set for both heating and water. There is a old manual thermostatic valve with a capillary tube attached to side on tank fitted in the hot water circuit but opening or closing this made bugger all differnce to the hot water tempreature.
Today using my humble DIY knowledge and several hours research on the Internet I fitted a tank stat and a wireless room stat (drayton RF3) . Powered everything back on set controller for heating and water and all seemed fine, both the room stat and cylinder stat working OK. Room came up to tempreature in around 30 mins and the room stat shut off the 2 way valve in the heating cirucit, within 2 minutes of this happening banging noises from the boiler and it shut down with overheat light. Let everything cool down and tried again exactly the same as soon as the heating valve shut down overheat in less than 2 minutes. Tried with just water and no heating and again shut down in under 2 mins.
The hot water is warming up, and there is a manual bypass valve fitted in the flow and return of the boiler.
Didn't have this issue on old boiler, there again it was 25 years old with a corroded heat exchanger and probably not giving out as much heat as the new one.
To me it seems like the hot water circuit can't take the heat away quick enough and hence the overheat, I'm a total novice at heating systems but the hot water cylinder itself looks a bit odd, all the indirect cylinders I've seen have the feed for the coil entering on the side of the tank this one (looks really old) has the feed entering and exiting via 15mm pipes via what looks like an immersion plug in the top of the tank, the pipe is reduced down to 15mm from the 22mm feed from the pump.
You can see a picture of the top of the tank at
http://www.mjspc.demon.co.uk/hwc.jpg
Is this just an old tank or has somebody bodged together some sort of indirect cylinder, seems strange it should only have a 15mm feed to the coil.
Any help or advice much appreciated.
Cheers.