I had a Gledhill Boilermate Thermal store fitted when we had Solar hot water added to the house, the old Megaflow and motorised valves were removed. I'm no plumber but I've had to learn a bit because of the mess the Solar fitter left - we had CH on permanently, Boiler circuit thermo-siphoning, leaks and CH thermo-siphoning so he came back to fit a non-return valve on the CH and Boiler returns. Unfortunately the CH still circulating to the top 3 radiators after the CH pump is turned off until all the water in the Boilermate is down to 30C. Gledhills have suggested adding a "London Loop" at the Boilermate but I'd rather be 100% sure and fit the original motorised valve back again. Can I wire the valve to the same electric circuit as the CH pump (controlled by the Boilermate timer), or does the valve have to be controlled separately to open just before the pump starts so there is no pressure build up & wear on the CH pump? If I wanted to drain the system would I have to remove the CH return non-return valve or would the CH empty/drain OK through the non-return valve if the motorised valve was closed? Hope this layman's explanation makes my question clear! Cheers
Hi steviec, Personally I would get the installer to correct the faults. But if this were no longer possible then I would opt for the London loop and fit an air vent and drain off within it for venting/draining purposes. With regard to the none return valve, if its a spring loaded type, it will hold back water when trying to drain down so you need to fit a drain off point as well. The fitting of a motorized valve to control thermo- cycling/siphoning is not the best way, as the characteristic way that they operate is that there will be a slight delay when switching/mechanical movement takes place. This will have an adverse effect on the life of the pump unless the pump also has a similar delay. The other point you ask about with regard to draining is, on the motorized valve, there is a spring lever which should be latched into the locking position for filling and draining purposes.
Mr Mistery Thanks for the info. I would get the fitter back, but I've had enough of him making mess of things to be honest. He denies liability for the thermo siphoning and says he's done "everything reasonable" to try and resolve it and thinks I'm being too fussy! From talking to Gledhills I understand the London loop is an extra rise & drop on the CH flow .. the piple already drops about 40" from the Boilermate before it goes straight up to 1st floor. How big a rise & drop should I add? Could I utilise the existing drain valve on the bottom of the CH flow drop or should I fit another drain valve on the the second lowest part of the loop where it exits upstairs? I guess the air vent goes on the highest part of the loop where it some from the water store . Finally, stupid question .... I guess the pipe SHOULDNT be lagged to allow the water to cool and break the siphon? Cheers
Hi stevieC, Yes, you need to fit an additional loop in the vertical flow pipe that's going upstairs. IMPORTANT NOTE< BE CERTAIN THAT ITS THE FLOW PIPE YOUR WORKING ON. If not, it will still circulate having fitted the loop. Picture this, at say a height of 6ft, cut out a piece of pipe 1ft long. Fit a tee onto the 6ft pipe and then fit a short piece of pipe into top say 6" long and fit an auto-air vent onto it. This will create an air bottle to help you fill system. From the side of the tee fit a short pipe and an elbow facing down for the drop loop say 5ft long,(the longer the better) fit another tee with a drain off to it, then run from tee to position of flow to upstairs. Lagging should not effect it, the loop should work with or without lagging. Make sure the problem is not being caused by two pipes touching one another, or the trouble may still exist, like flogging a dead horse. Good luck.
Forums
Facebook
Twitter
You Tube
Instagram
Shop