Central Heating Zone Problem

by **benmaye** » Tue Nov 04, 2008 1:51 pm

my central heating system is giving me problems. upstairs the radiators are hot. downstairs, they sometimes are hot and othertimes no heat at all. I have checked the usual with no joy. there is only one thermostat in the house and as upstairs is hot, i have illiminated this. Both the motorized zone valves have red hot pipes on both sides, so they are open (never know whether they should be set to open or auto!?!). occasionally the pipes leading to a radiators downstairs is tepid.

1. Is my problem a brockage?
2. how do I treat this?
3. and should the zone valves be set to open or auto?

many thanks guys,

Ben Maye

by **TheDoctor4** » Tue Nov 04, 2008 4:33 pm

Hi

Have you had a chance to have a look at the DIY Projects area: https://www.diydoctor.org.uk/projects.htm There are numerous projects related to Central Heating that may help you with your problem.

Regards

by **benmaye** » Fri Nov 07, 2008 4:58 pm

Thanks for your reply and there are some interesting topics there but they do not cover my problem.

Additionally, I have found that by shutting off the upstairs radiators, the radiators downstairs work fine. I am then able to turn the upstairs ones back on and everything heats up properly.
I could guess at a pump that isn't pumping properly, but can anyone confirm this or specify the fault please?

many thanks,

Ben

by **crwgroves** » Sat Nov 08, 2008 1:26 pm

[quote="benmaye"]Thanks for your reply and there are some interesting topics there but they do not cover my problem.

Additionally, I have found that by shutting off the upstairs radiators, the radiators downstairs work fine. I am then able to turn the upstairs ones back on and everything heats up properly.
I could guess at a pump that isn't pumping properly, but can anyone confirm this or specify the fault please?

many thanks,

Ben[/quote]

Ben,

It sounds to me that the gatevalves on your radiators are too open on the upstairs radiators. ie the exit valves on the radiators. Are the upstairs radiators closest to the hot water tank/pump? If they are it probably means the exit valves on the radiators closest to the pump are too open. this means that all the water is running through the upstairs radiators and returning to the tank on the return circuit before getting to the downstairs radiators. Try closing the exit valves on the upstairs radiators a bit (not completely) and see if the hot water reaches the downstairs radiators. If they do this is your problem. In theory the radiator nearest the pump should have its exit valve just open and each radiator in turn open a bit more until the exit valve is fully open on the last radiator in the circuit. The in-valves on all radiators should be fully open. I hope this helps.

Chris