Zoned central heating problem

[fredfat]

Hi,

I have central heating as follows; Ideal combi boiler 30, 3 rads upstairs 3 rads downstairs. Controlled with wireless enabled 2 zone programmer and 2 wireless room thermos. There are 2 x 2 port motorised valves on the return pipes.

I was told that it was a dual zone system and it was installed only 3 months ago, but there is a problem. When I switch a zone off i.e. upstairs ,the rads still get warm in that zone, once the other zone (downstairs) comes on and vice versa.

I have checked the motorised valves and I think they are working, based on the return pipe of the zone that is turned off being cold.

I have spoken to the installer and he said it's a problem they have had with a few installations and they don't have a fix for it, then mentioned something about the valves not working due to not having enough radiators fitted! Which seems odd that they would install it in the first place.

Any suggestions or advice as to what the problem might be would be gratefully received

Fred.

 

[Ollieg]

Maybe gravity circulation is the cause of your problem or you need another external bypass fitted to take some pressure of the closed 2 port.
Ask the installer if he thinks this might help.

 

[fredfat]

Thanks for your fast reply Ollieg I will be speaking to installer on Monday as I'm not happy just to leave it, and I will put your suggestions to him. I had wondered if hot water might just be running back into the rads that should be off via gravity but, and please excuse my lack of knowledge I thought because the upstairs rads where getting warm and they are on same floor as boiler then it couldn't be gravity.

Also i forgot to mention that when the downstairs is off (zone2) it is only 2 of the rads that get warm they are on the same flow and return but the other rad stays cold !! I,m wondering if the pipework as been installed incorrectly do you think this could be possible? again many thanks for your help

 

[Dotty]

You've a combi. Hot water will have nothing to do with it. And it certainly shouldn't be gravity!

You need a bypass fitted. You also need them to doublecheck the controls wiring. And they should also check the balancing.

 

[fredfat]

Hi Croppie thanks for your advice, I don't think i explained myself very well in the last post when i mentioned hot water i was meaning the hot water from the zone that is switched on running into the zone that is switched off.

I will mention the wiring to him, though the valves do appear to be working. Can I ask what a bypass is just so I'm clueded up when i speak to him. again many thanks for your help

 

[Dotty]

Your boiler has something called pump overrun which protects the boiler. An automatic bypass provides a route for the water to flow when the zone valves are closed.

You've definitely a combi yes? And a hot water cylinder?

Your house doesn't sound huge! Two bedroom?

 

[happyflyer]

You've a combi. Hot water will have nothing to do with it. And it certainly shouldn't be gravity!

You need a bypass fitted. You also need them to doublecheck the controls wiring. And they should also check the balancing.

These are good suggestions by Croppie, you might also try reducing the speed of the pump if it's multi speed, hopefully its outside the boiler case, phew, that will reduce the overall pressure and like Croppie say check the wiring, test that when both valves are closed the pump goes off , I know its too late now but there are loads of electronic radiators valves that have time and temperature control, you would not have any of this and you would not be stuck with just two zone every room would be a zone, you still need to make sure that water is going around the boiler when the system flow drops off.
In any case has the boiler got a bypass its a must for any boiler, another point, how old are the 2 port valves, if they are pretty old I would take them out of circuit and test them, you may find they are passing and the rubber balls have grooves cut in them due to wear and tear, your plumber says there are not enough radiators fitted that's why they are passing, tells me all I need to know about him "CB". and that's not an in car communications system, come back and tells us more we love it,

 

[Dotty]

Just reread your post, you mean HEATING water, not hot water yes?

 

[happyflyer]

Just reread your post, you mean HEATING water, not hot water yes?

Doh!:tongue3: yes/no keep you guessing cropppie :bigcry:

 

[Dotty]

Found myself thinking "What have these clampetts done here?"

 

[fredfat]

yes i mean heating water, its a combi boiler an ideal 30 but i dont have a water tank. the house size is 3 bed semi i would say average size if there is such a thing. Thanks for explanation of bypass valve. They have installed 3 double rads down and 3 single upstairs.

 

[happyflyer]

yes i mean heating water, its a combi boiler an ideal 30 but i dont have a water tank. the house size is 3 bed semi i would say average size if there is such a thing. Thanks for explanation of bypass valve. They have installed 3 double rads down and 3 single upstairs.

Sounds like a brand new system Croppie, what about that pump, plumbers always leave them on full throttle????

 

[fredfat]

hi Happyflyer, the whole system is brand new well 3 months. I'm in agreement about the not enough radiator comment. I will be speaking to the chap again on monday and feel more confident now that you chaps have given me some advice many thanks

 

[happyflyer]

Croppie,

The problem is when we explain to Joe Public we think they know how to tweak things, they don't half the time, even the plumber that fitted it don't know, the chap with the no water shower I tried to explain out to fit a simple purge valve me and you would have it in and fixed an ten mins, he had not got a clue. Yet the plumber at B&Q told him to fit a NRV in the shower riser pipe, see what guys are like at B&Q, how daft can you get.

 

[happyflyer]

hi Happyflyer, the whole system is brand new well 3 months. I'm in agreement about the not enough radiator comment. I will be speaking to the chap again on monday and feel more confident now that you chaps have given me some advice many thanks

What about the pump speed Fred I am flying blind in cloud :angelsad2:

 

[happyflyer]

Red thingy magig knob 1,2,3 Fred hope you haven't paid him in full

 

[fredfat]

I wouldnt have a clue regards what speed the pump is set sorry, I have know technical knowledge and certainly dont intend to be making any adjustments myself. I'm really just looking to pick the brains of people with experience so when i speak to the installer i have a little knowledge. and yes the firm has been paid as they completed the job i have only discoverd the problem in the last few days

 

[happyflyer]

Good luck then Fred, come back if you are not happy with his good time bed stories and his tall tales, the plumbers from :reddevil:

 

[fredfat]

Cheers Happyflyer, could I ask you another laymans question please? as the 2 zone valves are on the return side there are 2 return pipes going back to boiler, does that mean that the flow side feeds All the rads or will that also be split into 2 zones ?

 

[happyflyer]

You will have one main flow and one main return back into the boiler, somewhere down line both pipes will split into two, it is unusual these days for a plumbers to fit valves on the return they are normally fitted to the flow, but it matters not and in fact that is where the water is the coolest, the valves will run cooler and may last longer.

The return is split into two and he has put a valve on each, that's Ok, BTW is the system a sealed system, in other words do you have a filling loop he has shown you how to top up the system.

 

[happyflyer]

Fred,

At this rate you will soon know more than me...:rockon2:

 

[fredfat]

yes its a sealed system with filling loop and he did show me how to use it briefly! So just to clarify the flow will be split some where to feed the 2 zones independently ? cheers

 

[fredfat]

I doubt that . My worry is that I might have more knowledge than the chap i hope is going to make it work haha

 

[plumber0808]

It's a pipework problem, if they have had the same problem before then they are getting it wrong every time.
Why fit the 2 port on the return? Boiler flow on to bypass on to 2 port valves one feeding down stairs one feeding upstairs.
the return should have one circuit for downstairs one circuit for upstairs teed in together close to the boiler.

 

[fredfat]

Hi Plumber0808 and thanks for your reply. Since they haven't fitted the valves in the flow side even if they have at some point split the flow into 2 how does the heated water not run through all the rads ? please excuse my ignorance if this doesn't make sense