Zoned central heating problem

[happyflyer]

Automatic bypass valve should look like this

 

[fredfat]

Hi Happyflyer ,

Thanks for all your time and help. Sorry I didn't reply but got called away.

My system looks very much like your first drawing minus the bypass valve part. I cant see that anywhere. However on reading the boiler manual it says there is an automatic bypass inside the boiler, but then goes on to say if the system employs thermostatic radiator valves on all radiators, or two port valves, then a bypass circuit must be fitted with an automatic bypass valve to ensure a flow of water should all valves be in the closed position. Which means you where spot on!

Is there anywhere this could be installed that i would be able to miss it i.e under floor boards or would it be as it appears in your drawing?

One final question does the size of the pipe increase/decrease the pressure? the reason i ask is that it has been installed using a 10mm plastic pipe which seems very narrow compared to the copper pipes coming from and to the boiler.

Many thanks for your help

Fred

 

[jam1979]

why dosent your plumber put the zone valves on the flow and piece the pipes back on the return

 

[happyflyer]

Hi Happyflyer ,

Thanks for all your time and help. Sorry I didn't reply but got called away.

My system looks very much like your first drawing minus the bypass valve part. I cant see that anywhere. However on reading the boiler manual it says there is an automatic bypass inside the boiler, but then goes on to say if the system employs thermostatic radiator valves on all radiators, or two port valves, then a bypass circuit must be fitted with an automatic bypass valve to ensure a flow of water should all valves be in the closed position. Which means you where spot on!

Is there anywhere this could be installed that i would be able to miss it i.e under floor boards or would it be as it appears in your drawing?

One final question does the size of the pipe increase/decrease the pressure? the reason i ask is that it has been installed using a 10mm plastic pipe which seems very narrow compared to the copper pipes coming from and to the boiler.

Many thanks for your help

Fred

Fred,

If there is no bypass valve on the system then when say the 1st flr valve is closed and the GF open the system pressure will be higher and there will be a tendency for the pressure to try to push against the sparing in the valve that is closed, hydraulics are not simple, I did ask you what the pump is set at and its probably in the boiler case so you can't get at it. He needs to fit a proper bypass valve, I will have a look at the boiler instructions did you tells what the boiler was

 

[happyflyer]

Fred page 9 of Installation Instruction


Boiler Control Interlocks
Central heating systems controls should be installed to ensure
the boiler is switched off when there is no demand for heating, in
compliance with Building Regulations.
Heating systems utilising full thermostatic radiator valve control
of temperature in individual rooms should also be fitted with a
room thermostat controlling the temperature in a space served by
radiators not fitted with such a valve.
When thermostatic radiator valves are used, the space heating
temperature control over a living / dining area or hallway having
a heating requirement of at least 10% of the minimum boiler heat
output should be achieved using a room thermostat, whilst other
rooms are individually controlled by thermostatic radiator valves.
However, if the system employs thermostatic radiator valves on all
radiators, or two port valves, then a bypass circuit must be fitted
with an automatic bypass valve to ensure a flow of water should
all valves be in the closed position.



Fred,

My English is poor but this is what they should have said

or two port valves, then a bypass circuit must be fitted
with an automatic bypass valve to ensure a flow of water is maintained within the boiler, should
all valves be in the closed position.

Tony

PS I have noted the pump is in the boiler case to stop people adjusting it, how sad is that, its not a hanging offence to adjust the pump, never mind the buzzcocks 😛unk:

 

[leethegasman]

Hi,



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.


Fred.

Can I just ask when you have one room stat on and one off do both upstairs and downstairs radiators get hot.if this is the case take no notice of my post.but if when you turn on your downstairs room stat your upstairs radiators come on.and when you turn on your upstairs room stat your downstairs radiators come on
The reason I am asking I can not tell from your post.if this Is the case the room stats are controlling the wrong zone and is a simple fix.

 

[fredfat]

Hi Tony,

I will be speak to installer tomorrow and will be requesting that he comes back and fits a bypass circuit with an automatic bypass valve as it seems he should of done in the first place !

As you have mentioned about the pump being inside the case I'm i right in thinking that i'm not allowed to remove the case?

Once again many thanks for your time and help with this

Fred

 

[fredfat]

Hi leethgasman, thanks for your reply, the room stats are controlling the correct zone valves it is just that all the rads are getting heated instead of just the zone that is requesting heat. I think with the help of Tony and Croppie the problem has been found to be the lack of a bypass valve on the system and potentially the pump being set to fast.

Fred

 

[fredfat]

Hi jam1979, thanks for your reply as you may see from other post's it seems as thought the problem has been identified cheers

Fred

 

[fredfat]

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?

Hi Croppie,

Thanks for your help looks like you where spot on, will be speaking to the installer tomorrow and getting him back to install an autobypass as per yours and Tony's and installation manuals advice. Cheers

Fred

 

[Nostrum]

Zones valves on flow, bypass fitted. Jobs a good un. Sounds like its not necessarily caused by circulation. Heat rising into a few of the radiators upstairs. Do they get roasting hot, or warm on top? How long do they take to warm up if only downstairs zone is on?

 

[fredfat]

Hi Nostrum ,

thanks for your reply, my system and problem is 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.

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.

The rads upstairs don't get as hot as down stairs but they get warm fairly quickly. I don't think the water is being circulated as such in the zone thats switched off as the return pipe remains cold. The same thing happens if upstairs on and down stairs off with the exception of 1 rad that i think is the last in the system

Fred

 

[fredfat]

Hi,

Just quick update spoke to Engineer this morning and he is going to come out and look at the problem. No mention of not enough rads ! so fingers crossed he has forgot about using that as an excuse. I will let you know how it goes. cheers

Fred

 

[rob2048]

Hi your zone valves are on the flow not return pipes if they have used one return pipe and not two separate returnes the hot can creep up the one that is turns off we have had this now we always run two seperate returns and link in just before boiler hope this helps

 

[fredfat]

Hi Rob, thanks for your reply, the valves are defiantly on the returns and there are 2 returns 1 for each zone. Cheers

Fred

 

[leakeee]

dont ideals come with built in by-passes? If valves are on returns are they the right way>?

 

[rob2048]

Hi Fred I've never put them on the return if they are on the return what's to stop the heat on the flow going where it wants Evan with one return it only creeps up getting the nearest rad warm you must have linked them somewhere is a new build might have put a downstairs rad in upstairs loop or other way round easy mistake to do

 

[happyflyer]

Hi Fred I've never put them on the return if they are on the return what's to stop the heat on the flow going where it wants Evan with one return it only creeps up getting the nearest rad warm you must have linked them somewhere is a new build might have put a downstairs rad in upstairs loop or other way round easy mistake to do

Rob,


I agree, you need to put the barrier on the hottest pipe work which is the flow, hells-bells Fred this is 50 posts now you should be able to fit a heating system yourself, albeit push fit plastic. When your plumber comes around, show him the posts here, there are some little nuggets of information.

Tony

 

[fredfat]

Hi Guys,

Just had my heating sorted after a short 4 months wait! just glad we've had a nice summer. Anyway just thought I would update you on what the issues were.

1st no by-pass circuit installed.
2nd zone valves on return instead of flow.
3rd 2 flow pipes fitted (1 to each zone) but only 1 return for both zones.

Pleased to say that the chap today knew what he was doing and has put it all right. Thanks for all your advice, looks like everyone on he was correct in one way or another.

cheers fellas

 

[leethegasman]

Hi Guys,

Just had my heating sorted after a short 4 months wait! just glad we've had a nice summer. Anyway just thought I would update you on what the issues were.

1st no by-pass circuit installed.
2nd zone valves on return instead of flow.
3rd 2 flow pipes fitted (1 to each zone) but only 1 return for both zones.

Pleased to say that the chap today knew what he was doing and has put it all right. Thanks for all your advice, looks like everyone on he was correct in one way or another.

cheers fellas

Nice to here you got some one in to put right