Rads heating when they shouldn't!

Neil_Sedaka

Hi all,

About 3 years ago I had a new hot water tank installed, along with a motorized valve, a new Ideal Classic boiler and a new Siemens RWB29 Programmer.

Lately, when the system comes on to heat the hot water only, the rads are now heating also!

I'm thinking that the motorized valve may be stuck (open or closed?)
The small red light on the valve casing lights, so I assume it's getting power.

Any thoughts or suggestions please?

Thanks.

DoneDL

If you select heating only does the hot water pipework heat up?

aujopimur

Check the man/auto lever on the actuator. if this is not the problem remove it and see if it opens /closes when you switch on/off, if this ok use a pliers to see if you can free the valve as it may have stuck when not in use.

Neil_Sedaka

DoneDL wrote: »

If you select heating only does the hot water pipework heat up?

I can't select heating only as once the boiler is on, it heats the water anyway.
I can select water only from the programmer, but all that does is close off the supply to the rads (which it's currently not doing)

Neil_Sedaka

aujopimur wrote: »

Check the man/auto lever on the actuator. if this is not the problem remove it and see if it opens /closes when you switch on/off, if this ok use a pliers to see if you can free the valve as it may have stuck when not in use.

Thanks, I'll need to take a good look in the hot press, as I'm not really familiar with the valve operation. I don't/didn't think I had any lever I could turn.

aujopimur

The lever is part of the elect actuater, its quite small and not easily visible depending on how it's mounted.
If as you say the ind. light is on when not calling for heat it points to MV stuck open, when you remove the actuater it should become clear where the problem lies.

Neil_Sedaka

OK, here's what I now know.

I have a Sunvic unit.

There is indeed a small lever that I can manually flick from left to right.
The ind light only comes on when I call for heat.

In both left and right positions of the lever, the rads are still heating.

Hopes this makes a bit more sense.

DoneDL

Apologies OP when you said one valve I thought you were referring to a 3 port valve. Why anyone would fit a valve to a gas boiler heating system that isolated just the heating without having a fully integrated system is beyond me. See if you are in a position to avail of the SEAI grant and fully update your system, failing that have an RGI look over your system as just heating your hot water without a bypass will not be doing your heat exchanger any good. The programmer is suitable for fully integrating the system.

Neil_Sedaka

Thanks DoneDL

We used to have a handle in the hot press that would "switch the rads off" for the summer months.

When we got the new boiler and programmer, I asked the fitter about having a summer setting and he suggested the motorised valve.
Seemed to make sense to me, but I'll admit to knowing little about heating systems.

Am I right in thinking that I can remove (how?) the casing from the Sunvic unit and then see an actual valve assembly, without flooding the place?
If so I might be able to twist the valve a few times as aujopimur suggested.

Thanks again.

DoneDL

Yes if the update was three years ago then aujopimur would be right in their post, I would suggest doing it when the system was cold.

aujopimur

The sunvic has 2 screws securing the actuator undo these, check that the drive turns when you turn on/off at the timer, it turns slowly so give it time to move.

Neil_Sedaka

Cheers guys, I'll take a peek tomorrow and report back.
Really appreciate the replies

Neil_Sedaka

Got it sorted thanks to the advice here.

I took the actuator off and it was working fine.
The valve was not fully turning, so a few twists with a pliers and now it rotates full circle.

Was a b1tch to get at, as it was buried in the back of the hot press, with no real access.
Leaned in with one arm and did the job blind, but did it all the same, thanks to the descriptions given.

A huge thanks folks, really appreciate it