Initially both central heating AND hot water stopped working completely. Through various small fixes, I’ve got the hot water back working, and a small amount of central heating. The system is: Indirect open vented F and E gravity system. Back boiler behind fireplace. Two tanks in loft (header and cold water). Hot water cylinder in airing cupboard, no immersion. 3-way motorised valve. Honeywell controls. Grundfos water pump. 9 Radiators. Things I’ve tried: Bled radiators, bled pump, bled air vents, opened all radiator valves fully, turned thermostats up high, checked header tank is full. After doing all this, the hot water started working again. Upstairs, 1 radiator now works fully and the other 3 are showing signs of heat. Downstairs, nothing from any of the 5 radiators. Any ideas/diy fixes/feedback will be much appreciated! Thanks.
Did you ensure that the cold feed is not blocked , as per your previous thread ? If you set programmer for central heating only ( no hot water ) does the pipe from the 3 port valve that goes to the hot water cylinder get hot ,and does the return pipe from the cylinder also get hot ? And does the boiler fire up and run in that mode ?
The cold feed doesn't appear to be blocked. However, the one radiator I had bled out half a pint of water (radiator was only getting a tiny bit warm), then it ran completely dry. The next day I turned on the heating and it had refilled and started working fully boiling hot. I've only just switched the hot water off and the heating on, so at the moment the 3 port valve going to the cylinder and the other way to the radiators are both very hot. The return pipe from the cylinder is cold. Yes, the boiler does fire up in heating only mode.
To the right side of the pump is a red ,round handled ,gate valve. Has it been closed at any time ? See if it is fully opened , anticlockwise. You have a circulation issue ,the pump may not be doing its job ,you may have a blockage / sludged up rads ,or a valve restricting the flow ( as above ). Do your radiators have thermostatic valves ?
Before I tried anything, the pump just turned itself off and isn't coming back on. The header tank overflow has a bit of water coming out of it. Any idea what this may mean? The gate valve to the right of the pump was already fully turned anti-clockwise(open). Radiators have no thermostatic valves.
Water coming out of the expansion pipe ? (That comes up above ,then down into the F&E tank) The overflow is the pipe that goes to outside . Which is it ? If the expansion pipe has water coming from it ,the system is pumping over and that's a sign of a blockage.
The overflow going outside is the one that has just started leaking out. Would that also indicate a blockage or something else? Pump not coming back on.
Is it the F&E tanks overflow ? The water level in that tank only needs to be a few inches. Why is it so high ? Could be it's float valve isn't fully closing, could be it needs adjusting to close when the float is lower. Nothing to do with pump not working .
Yes the F&E tank overflow. I noticed the leak and the stopped pump at the same time, so thought it could be linked. The header tank was more than half full last time I checked, it's situated in such an awkward position to quickly go look! Is it possible the pump has overheated and broke from a blockage and lack of water in the system?
Possibly. Without water ,the pump would run extremely hot and fail . Remove the screw and see if it is freely turning ,turn electric off first. It may be seized up .
Thanks Terrymac, the pump was only seized and not completely gone! When I removed the screw there was a lot of gurgling and air release. I manually turned the impeller, then switched it back on and it worked. Was a little noisy to start, but then okay.
I still think you have a blockage ,as per your original thread some time ago,and your system is being starved of water ,some pumping over is taking place and raising the level in the F&E. Pump ran dry and seized up as a result, all ultimately contributing to your circulation problems. You would be well advised to engage an engineer to visit and overhaul your system.
Unfortunately we are shielding and are unable to have anyone to the house yet. I would love nothing more than having a professional take a look at it and get it sorted ASAP, it's quite stressful. Thanks for helping out on this, I know it must be frustrating trying to explain everything. Depending on the type of blockage, what methods would you advise I could take? Might a cleaning chemical help breakdown any sludge, then try and release it from radiator drain valve downstairs?
If you have a radiator downstairs with a drain cock ,connect a hose and drain off ten or 15 litres ,and see if the F&E tank drains / replenishes quickly. It may help to add a chemical ,but unless you have good circulation it won't do very much. Cutting into pipework to clear or renew sections is very often the only way .
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