Rads downstairs cold

Have glow -worm boiler 12 years old regularly serviced ( 12 monthly ) fitted with new pump about two years ago (grundfos 25-50).

Problem, yesterday some downstairs rad were luke warm so I turned off upstairs and then all downstairs got hot ( fine ) but noticed one of upstairs rads went cold.
Today I switched off all rads except the cold one upstairs and turned on system - knocking sound etc .

Opened up all rads agAin but only upstair hot (except the same one upstairs problem rad).Decided to repeat yesterday exercise so I turned off all upstairs again to get downstairs working.Now they will not work!!!.Pressure gauge was originally at about 0.7bar , yesterday now dropped to 0.5 bar.

Boiler kicks in , gas burner is lit for about about 1 minute then cut off.Have I a Faulty pump - surly not after 2 years ...

Any help would be appreciated ..

madhatter

hi m8 sounds like the pump to me and that the heat is gravitating to the 1st floor

Hi fivebri,

Thanks for the reply .I decided to let the system cool down and then unscrewed the centre screw of the pump,only slightly but not the full way out , thinking I might get discoloured water ( sludge etc). However, water is clear but got some minor hissing/air . Re tightened screw , restarted the boiler , pressure went back to about 0.9bar, rads heated up .

All appears to be ok with the exception of the one solid cold rad upstairs !!!including the pipe leading into the rad.

If there is sludge could it have lodged and blocked this rad ? ,When I run the system , I listened to this rad and it sound as if it is trying to fill with water,,,, sounds hollow....

Any thoughts on how I can investigate this further .

Thanks for the help

bleed the rad

possibly stuck TRV

Hi Kev ,

Tried bleeding until water comes out , but still will not heat up : What is TRV ??

Never rains but it pours , now the shower has packed up last night . investigaed same and and appears the elements in the cylinder Can are gone- old triton T90 .Tried triton today for new cylinder CAN 8kw /240V-Had bathroom completely retiled last year now obsolete shower, no spare parts as per trition UK /Dublin distributor.Does anyone ,know of any suppliers who may have one of these ?

thank for the help on the rad.

madhatter

Thermostatic Rad Valve

A Chara Madhatter,

I managed to get some oddball parts in EuroHeat on the Greenhills Road. It's just behind the Plumb Centre after the Walkinstown Roundabout. They're pretty helpful and a lot cheaper than the Woodies/B&Q boys for stuff.

Le meas,
Forlopp.

Thanks mate - going that way today so I will have a look

madhatter