Lost Control part 2

Ted808 · Apr 18, 2012

Re: Lost control..?l

Hi guys an update....
Been there yesterday, and had a good look around ..
Like I said B4 it's a Gravity system- Baxi 30HE, Alpha (digi pump on 2), 2X 2 port valves,
(1050) HWC-set to 65~c, Big OLD CWSC and F+E tank, 12 rads.
2 bathrooms- towel rails-one on AND one-OFF!- guy said bathroom was getting too hot, so he shut the valves..here's the problem me thinks..he's shut the by-pass, SO this could be why his boiler locks out when he turns the room stat DOWN-YES?
But now the lockshields-fairly crudded won't open.. well i didn't want to try very hard cuz it was just a fault finding mission. BUT also while I was there, the F+E tank vent started spouting hot water... IS THIS ALSO CUZ THE BY-PASS SHUT_YES??

To me it sounds like a 2 port valve shutting off and bypass not open enough or not there but could also could be pump overun not wired in.

Alpha pump at boiler does turn off when I turned stat down after about 2 min-OK...? So the overun is wired in ?

The 2 TPV's seem to be operating but not quite sure how to test if there's a fault.
Had HW on one valve opened, had CH+HW on other valve opened, they also had resistance when closed... Was this the right way to check?
Anyway will appreciate your advice.....
-----Can you get a decent shower off a gravity system, the head is about 4-6foot, CWSC is raised. At the mo' they got a shower mixer bath tap and ...well... it's not going to work!! EVER! I think he's looking at electric or power shwr ?
Lastly, the thing with the pump was a pie in the sky, it's not connected!!!
I do like a bit of problem solving, with a little help from my 'friends' ...get me rusty bits going again...
Thanks for listening :1eye:

Millsy 82 · Apr 18, 2012

If he has shut off the bypass then yes that will be the problem with boiler locking out and the open vent overflowing. If it is seized then replace with a automatic bypass.

When I test the 2 port valves I see where I get 240V, Grey white and orange all ok when it should be on. Grey only when it should be off, Grey and white its a fault on it.

diamondgas · Apr 18, 2012

SO this could be why his boiler locks out when he turns the room stat DOWN-YES?

If you know for deffo that it's the system bypass then it is possible that when both zone valves shut off the latent heat in the boiler has no where to be pumped around by the overrun.

BUT also while I was there, the F+E tank vent started spouting hot water... IS THIS ALSO CUZ THE BY-PASS SHUT_YES??

Spouting as in running like a tap or spouting as like boiling over? I think you need to establish whether or not your theory regards the rad being used as a bypass is correct IMO 🙂

Alpha pump at boiler does turn off when I turned stat down after about 2 min-OK...? So the overun is wired in ?

The boiler didn't lock out then?

had CH+HW on other valve opened, they also had resistance when closed... Was this the right way to check?

This will let you know whether or not the motor is operating correctly but will not tell you that the microswitch inside the valve has fused .... You'll know that because the boiler will be firing or have a switched live present.

stevetheplumber · Apr 18, 2012

you can get a reasonable shower from 6foot of head no reason a bath shower mixer wouldn't work with that amount of head
aqualiser made their name by making thermostatic showers that run on gravity their logic was the couldnt increase the preasure so the increased the flow rate by feeding in 22mm pipe and using wide bore shower hoses and specially designed headsthey work and they seldom breakdown