underfloor heating not working !!

[andyjp007]

Hi

hope that you can help as i am freezing cold !

i moved into a converted farmhouse which was blessed with tiled floor in lounge, kitchen & utility - warmed by underfloor heating.

i am really struggling to get it working

i had a new JG timezone clock fitted, new wiring and 4 new JG actuators done about 2 months ago. it seemed to work ok, but not really needing it i turned it off.

i need it now...thermostat in utility now showing 8 degs.

i have had the boiler on all day on there seems to be no movement at all. i am 99% certain that the pump works, but the inflow temp gauge is showing approx 14 deg with the outflow gauge similar ; and despite boiler being on all day there is absolutely no movement (or heat).

i am at a complete loss as to what to do.

any advice would really be appreciated

thanks

 

[Norcon]

i am 99% certain that the pump works

How did you ascertain this?

 

[andyjp007]

hi

because i can fee it vibrating.

there are 3 settings, as i move though 1-3 i can feel it stop/ start / stop; so i am sure that it works.

i am trying to do some more investigation, and i am wondering whether it has been plumbed correctly.

my suspicion is driven by a t pipe which is before the pump.

the base of the t pipe ( direct from the boiler is scorching hot). the T bit leads to the pump and inflow to the system.

the other bit of the t is cold water direct from the system ( this pipe also has an off shoot further up which i presume is going back to the boier).

what i see happening at the moment , is hot water coming up, and simply hitting a wall of cold water !

having looked at some schematics i wonder if this is right ?

also ( after looking at some schematics) i wonder whether there is a pump 'missing'.

there does not seem to be a pump near the boiler, so i am now wondering if it is under 'pumped'

any thoughts be appreciated

thanks

 

[Norcon]

Given what you explained above it looks like a direct path from the ufh return back to the pump is fitted.
Normally that path will flow through one port of a three port valve assuming its not an injection system.

Flow will follow the path of least resistance!

Is their a mixing valve fitted to the pump return?

Normally a primary pump is used and provides positive pressure to the tmv inlet via the primary pump. A by-pass should be fitted to balance this pressure.
It wouldn't be the first time these systems are piped up wrong and won't be the last.

 

[andyjp007]

thanks

yes, there looks like a flow back to to boiler.

on the t junction is a mixer valve. obviously hot water from boiler comes in one pipe / the other pipe feed from the 'out' bit of the uf / with the 3rd pipe going to the pump which is going to the manifold and into the actual uf sysyem

the pipe which comes from the 'out' of the uf manifold into the t junction mixer has an off shoot which i am guessing flows back to the boiler to create the loop.

i was looking at the jguest 'installation video' for the manifold yesterday and mine is plumbed different. specifically the 4 actuators are on the cold 'outflow' manifold not the 'hot' inflow manifold. i spoke to my electrician yesterday who rewired the system a couple of months ago about this ; he said that he had spoken to the JG technician about this who said it was ok.

i assume therefore that it is

my latest query...having been talking to my plumber yestefay is whether the zone valve actuator for the uf system has broken. the manual override swithch is stuck so i cannot try to kick start it that way.

any other suggestions would be appreciated

regards

does this

 

[Norcon]

on the t junction is a mixer valve

Can you see any name on this valve?

Manufacturers recommendations regarding the fitting of this valve should be sought.

JG's website seems lacking on information. The JGCONTROL/2 mixing valve looks like a Reliance valve with the JG logo.

As you only have one pump my guess is the flow is taking the easiest route through the three port valve.
Which will be the cold port.
The hot port on a lot of these valves have a restrictive piston and valve seating arrangement and require a pump on the primary circuit to provide the necessary pressure to overcome the resistance it creates.

 

[Norcon]

Yes all JG's mixers are Reliance manufactured and do indeed need a primary pump according to Reliance technical advice.

Either website does't make that very clear!
Rehau do make it clear and they use a Reliance mixer for small systems.

Pointless exercise calling JG technical.

 

[Agile]

Why dont you get your plumber to come and sort it out?

The stuck valve is an immediate suspect!

Tony