DV failure?

[QuackingPlums]

Hi,

I have a 3-storey house with a boiler and CH programmer downstairs and a MegaFlo tank on the middle floor (in an airing cupboard with lots of pipes).
There is a simple dial thermostat on the ground floor and a more sophisticated electronic one on the top floor. Right now the programmer is set to manual "ON" and the thermostats are both cranked right up.

Problem: I think one of my DVs has broken/seized because the middle and top floor rads don't come on. In my airing cupboard there appear to be three DV units; one that feeds hot water into my tank and two that presumably feed separate rad circuits. I have lots of hot water.

I have checked the FAQ/Wiki and by switching the "cold" DV to manual, the upper floor rads are now hot. I'm guessing I need to get a plumber hot to replace/repair the DV, but is it safe to leave the valve in manual for now?

Thanks in advance!

 

[Agile]

You can do that with the heating ones.

But NEVER with the one for hot water!

Tony

 

[QuackingPlums]

Thanks for the reply.

I should add that I know NOTHING about central heating systems, and switching the DV to manual was something I just found by reading up on here.

Am I right in thinking that with it left open in the manual position, that the rads on that circuit will be "on all the time"?

 

[ScottishGasMan]

The water circuit to those rads will be open all the time, but the chance's are once your HW cylinder has reached temperature and you turn off the other heating at clock/thermostat then the manually opened circuit will also cool off.

(not guaranteed, but the most common setup for these valves would act like this)

Perfectly fine to leave it open on manual, chances are the motor in the valve has packed in, but could also be fault with the timer or if you have one, room thermostat for that zone not telling the valve to open.

As said, don't open the valve feeding the hot water cylinder if you ever have bother with that.

 

[QuackingPlums]

Bizarreness ensues. Having left it manually set open for a week or so, the actuator started clicking loudly every second, so I decided it was time to call the insurance people. I have full central heating cover (apparently!) so they sent someone out to replace both of my DVs - for both zones. Now the upper zone is stuck OPEN, and is on whenever the CH programme is active on my boiler.

Adjusting the thermostat in my hallway correctly closes the ground floor circuit when it reaches my desired temperature.

Adjusting the thermostat in my bedroom to off (or as near to "off" as I can - it's a Siemens REV23 that only appears to have 'eco' mode), the circuit for my upper floors just stays on all the time.

Looking at the DV itself, the sprung manual level can be moved easily, indicating that it is wide open? Is there a way to check if the DV is faulty, or whether it's my thermostat that isn't sending the signal to close the circuit?

At least the clicking has gone away! lol