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Andrew Smith
Andrew Smith, HVAC Technician
Category: HVAC
Satisfied Customers: 3768
Experience:  Heating and Controls engineer
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Hello there, Can you help? weve returned from holiday to

Customer Question

Hello there, Can you help?

we've returned from holiday to find that our hot water is working but not our heating. we've got the Honeywell ST9400C thermostat model. What should we do to get the heating going?

Many thanks,
Submitted: 3 years ago.
Category: HVAC
Expert:  Andrew Smith replied 3 years ago.

Andrew Smith : Can you find the motorised valve in the airing cupboard?
JACUSTOMER-rahqkvya- :

Hi There, sorry for delay I've been out this pm. Yes, I think I've fund the motorised valve in the airing cupboard. the make is Grundfos. on the side there is a switch with 3 settings: 1 / 11 / 111. he dial

JACUSTOMER-rahqkvya- :

sorry I didn't finish........1 = 0.16 / 35, 11 = 0.20 / 45, 111 = 0.23 / 50. the dial is currently on the '1'. also by this there's a pressure dial; the black hand is currently below the 1 and the red is just below the 2. does this seem low? any helpful to get my heating on tonight would be most gratefully received! thanks so much.

Andrew Smith : That is the pump
Andrew Smith : The motorised valve will have 2 or 3 pipes going to it and should be white or silver?
Andrew Smith : Drayton or Honeywell?
JACUSTOMER-rahqkvya- :

I've just looked and there are 2 white boxes on the wall. one says Honeywell 240k danger, the other one has a button with a green light on. However, just tucked behind the tank is a configuration of pipes coming in to a junction with a red valve turning and higher up a sliver valve turning. above the silver switch is a blue lever (my guess is cold water) as on the ground at the bottom of the pipes there are 2 red levers. I'm so sorry, I haven't given you many clues at all. British Gas are coming tomorrow evening so if I've confused you, please don't waste your evening!"

Andrew Smith : ok, but if you can find you motorised valve and it has a lever on the back end you will be able to get heating while your hot water is on by pushing the lever and latching it
Andrew Smith : This will work until they can get to you and replace the valve
JACUSTOMER-rahqkvya- :

ok, last try and then I must let you have your evening! I've just noticed 2 silver / tin-looking boxes in different positions on the pipes, with a Honeywell label on. These silver boxes have a pipe junction coming in to them at the bottom. also coming in to these boxes is a black lead, which at the other end goes into the white box that says 240k danger. on the side of each box is a silver lever that can be pushed across to the other end. Could one of these be the heating valve?

Andrew Smith :

Yes - one will be for the hot water and the other for the heating - when powered on then the lever on the bottom should be slack.

Andrew Smith :

I suggest that the heating one has failed - if you push this one open and latch the lever then you will get heating whilst the hot water is running

Andrew Smith :

This should keep you going until you can get it swapped out