help neeeded asap please

[wolfiehogan]

hi guys
went to wire the heating for a house today but had problems with it. the house could not be zoned properly as the rads where plumbed wrong. the house has a mv for the hot water and upstairs heating and its working fine. i have them wired with the auxiliary bringing on the boiler. however the down stairs heating has no mv and the plumber just said to have the channel for downstairs bringing on the boiler.
my problem is that when channel 2 for upstairs is on and downstairs channel is on the downstairs stat will not turn off. this is beccause the stat is feed from the time clock and is live at one end and when channel 2 is on it is back feedin back to the stat so its live at both ends. how do i get out of this.
hope some one can make sense what i am trying to say
thanks

 

[Deleted member 9648]

Use a relay energised by the downstairs stat and feed the boiler through the N/O contacts.

 

[wolfiehogan]

i was thinking that myself but was afraid that when the contactor is energised that i would be in the same position i am now, thanks for the reply wirepuller

 

[Markc]

If there's only one MV for the upstairs heating and DHW and none on the downstairs then it will never work correctly. The client will not be happy and it will not comply with building control.

If the Plumber has screwed up why try to cover his arse? I bet he wouldn't do it for you! If its not plumbed right trying to over come it with the electrics will never rectify it.

 

[Mark_Burgess]

hi guyscould not be zoned properly as the rads where plumbed wrong.
thanks

Enough said, their problem not yours, if the shoe was on the other foot no favours would go your way. Just the way it is unfortunately.

 

[robsparky1975]

What programmer is there? 3 channel,i do quite a bit of these,you probably have good knowledge,plumber has created a problem that client will surely be fed up with/will they still pay you if its not your fault,i hope so

 

[Deleted member 9648]

If there is a separate heating circuit for downstairs but no valve there must be a separate pump for that circuit ,in which case there is no reason why the system cant work properly.
Feed the downstairs stat from htg ch2 of the programmer and use the return to energise a 2 pole relay. Link a permanant live to the common of each pole and from the N/O contact of one pole feed the boiler and from the N/O contact of the other feed the pump for the downstairs heating. When the stat is off there will be no backfeeds to the stat and pump as the relay contacts will be open.................If there is no separate pump I agree with the others,there would be no way the downstairs circuit could work correctly without a MV.

 

[wolfiehogan]

there will be no extra pump. it is planned to heat downstairs just by the boiler running and if the upstairs valve is closed there fore it wont heat the upstairs.
i tried to wire it today through a relay but it would not work properly. i wired the n/o contactor by energising it from downstairs stat and took a permanent feed to one end of the contacts and wired the boiler in to the other end of the contactor.
wen testing the downstairs channel the contactor dropped in and out as normall but when ever i put on the other zones they would not let the contactor drop out as when i would try to turn off the stat downstairs which controlls the contactor it would not go off with the other zones on. i have no idea why this is,
can any1 help i cant understand why it didn work

 

[Deleted member 9648]

Trying to work this one out.....is the system pump controlled by the boiler or by the M/Vs ?. You have one stat for up and one for down, correct?

 

[wolfiehogan]

thanks for your time
it is all pumped from the boiler.
have one channel controllin a stat upstairs that puts power on to a motorised valve and at the same time the valve energises and brings on the boiler. its the exact same for the hot water,
with the downstairs channel it controls a stat that brings on the boiler directly . the problem with is that when the all zones where on the stat was live at both ends from the time clock and the back feed to the boiler .this means that stat will not turn off. and its the same when i break it through the contactor, hope this is a bit clearer

 

[Deleted member 9648]

If the relay coil is fed from channel 3 of the programmer through a stat it can only be energised when the other zones switch on if there is a link somewhere between channel 3 and the other channels....draw a circuit diagram of exactly how you have wired the system and you will see if there is any where you are getting a back feed or link.
But from your description of the system I cant see how it can work with just one pump and no M/V on the downstairs,as whatever zone starts the pump/boiler hot water will pump round the downstairs circuit regardless of the state of the downstairs stat....you will have to get an MV to shut off the downstairs circuit for the system to operate with just one pump.