underfloor heating cold rooms

[theweecannyjock]

hi all, first time posting so go easy.
my underfloor heating system (plumbing) runs three zones, zone 1 kitchen, zone 2 bedroom and zone three lounge, very small hallway and small bathroom. problem is that zone three, is not quite right. lounge is hot but hallway and bathroom are freezing. all was ok last winter but this year these rooms are just stone cold. i have raised the boiler pressure up to 1.5 bar, raised the boiler thermostat control and raised the lounge thermostat, still freezing i have tried to bleed the system but everything is fine there. the boiler is a camray 5 oil fired system. the boiler was serviced in the summer, so im pretty stumped as i have tried all the basic things that i know. any help would be good. thanks in advance.

 

[Norcon]

Could be a seized circulator which can happen over a summer period of inactivity.Try removing the slotted screw in the end and turn the impellar shaft.

 

[xr4x4]

do you mean the rooms not warm/hot or the floor?

 

[theweecannyjock]

circulator ?? sorry friend my knowledge of the system wont stretch that far.

 

[theweecannyjock]

the floors are cold. the lounge floor which is on the same zone is hot but the hallway and bathroom floors are cold.

 

[simond]

I would imagine zone 3 shares a manifold and pump.

If this the case check the zone actuators on the manifold are opening. We have found sometimes people take them off and put them back in a different position, this will cause cold rooms.

 

[theweecannyjock]

hi simon they are all opening when i call for heat via room thermostat

 

[Norcon]

circulator ?? sorry friend my knowledge of the system wont stretch that far.

Also known as a PUMP.
See faq 14.
//www.diynot.com/forums/viewtopic.php?t=175736&start=0

 

[theweecannyjock]

hey noorcon many thx for your response. im getting heat into other rooms would this not indicate that the pump is already working. if i have this wrong please excuse my ignorance

 

[Norcon]

Yes it would of course. Just re-read your op.
Check the flow indicators on the manifold (if fitted) and see what flowrates are registering.
You could also try removing one of the actuater heads on a zone that is working and fit it on a non working zone.

 

[theweecannyjock]

no flow rate indicators fitted. the pump is running on number two would moving the pump to number three make any odds or am i clutching at straws

 

[theweecannyjock]

i have three floors running off the same zone. only one floor is hot what i cant understand is that the same zone is only heating one third of what is should. surely all three floors would either be hot or cold rather than one out of three on the same zone. its like one third of a radiator heating up and the other two thirds not. to me this would indicate a air problem which would require bleeding but as mentioned before, there is no air/bleed issue.

 

[mointainwalker]

i have three floors running off the same zone. only one floor is hot what i cant understand is that the same zone is only heating one third of what is should. surely all three floors would either be hot or cold rather than one out of three on the same zone

If the first room on the circuit is getting hot, then somehow all the heat contained in the water is being extracted in that room and there is none left for the other two.

What is the total circuit length ? What is the pipe-spacing ? Is it equal in all three rooms ? What are the m2 of each room ?

 

[theweecannyjock]

system was already installed when i purchased the property. all was well last winter. system is five years old

 

[Agile]

Its difficult to make any suggestions without seeing how its fitted.

Can you post any pictures of the pump(s), blending valves and manifolds?

Tony