Bypass Valves-any advice?

[Flyboy]

I am re-plumbing my system using the honeywell s plan etc using a room/tank thermostat plus zone valves to control water/heating. The system has a tendency to over-pump back through the header tank when the heating thermostat closes and most of the pressure is going through the hot water side. It was very badly plumbed to start with which is why I am starting again, contractor gone bust. To overcome the problem I am going to fit 2 bypass valves on the heating and the hot water side to stop the over pumping which has made a nice mess at the back of the house through the overflow. Is it necessary to fit two valves or is it normal just to fit one on the water circuit. Honeywell just say fit bypass valves on their website but leave it at that. I will have a lot more control on this system and for the sake of approx £70 two bypass valves seems the way to go. Already have the pump on its lowest setting. Any advice-jetlagged flyboy.

 

[ChrisR]

Sort out the pipework to stop pumping-over. That isn't waht bypass valves are for. It sometimes makes thing s easier to use a Myson Aerjc (Air eliminator) or similar. See BES.LTD.UK Basically a normal system should go

boiler >>vent>>(within inches)feed>> pump >> rads>> boiler

You may or may not need an auto bypass valve- though the building rgs now practically demand one. Shouldn't cost you more than £25. Try bes again.

 

[AnonymousImport]

You don't need two by-pass valves, just the one. Put it in after your pump but before your zone valves. As for the pumping over what speed is your pump on? It shouldn't need to be higher than 2 for an open vented sytem. Unless the system is a very large one. Pumping over also causes excessive corrosion within the system and it would probably be a good idea to add inhibitor.

 

[corgiman]

Two bypasses, are you sure you dont mean zone valves??

as for auto bypass read the manufacturers instructions to see if they insist, as a rule of thumb if it is a pump overrun boiler whack in a auto