Central Heating Problem.

[Ali Intisar]

I have a problem with my gas central heating. Following the design parts. A. Conventional Boiler B. Pump C. 3 port motorised valve. D. Room Thermostat. E. Cylinder Thermostat.

Problems:-

1. The 3 port diverter valve only moves visually when the heating is turned On.
2. It does not move when you try to bring the H/W On with it.
3. The boiler does not cuts off or On from the Room Thermostat.
4. The boiler comes on or Off with its on thermostat.( Boiler Thermostat.)
5. The boiler comes on even without programming for C/H.

I suspect the 3 port motorised valve but I can not explain to myself why?. please help me.

[Set Square]

Has it ever worked ok, and suddenly stopped working, or has it always been like this?

We need a few more diagnostics.

1. Select HW only on the programmer. Turn the cylinder stat to max. The boiler and pump should run and the 3-port valve should be HW (rest) position. What actually happens?

1. Turn the cylinder stat down until it clicks off. The boiler and pump should stop. What actually happens?

2. Select CH only on the programmer. Turn the room stat to max. The 3-port valve should motor to the CH position and *then* the boiler and pump should start up. [May take a few seconds] What actually happens?

1. Turn the room stat down until it clicks off. The boiler and pump should stop. What actually happens?

Answer these questions first, and then we'll start considering what happens when HW and CH are on at the same time.-- Cheers, Set Square ______ Please reply to newsgroup. Reply address is invalid.

[Ed Sirett]

Might be a diverter type of 3-port valve rather than a mid-position type. see main FAQ.