getting nowhere fast.

[stecod7]

help with a capital H**** having problems with my gravity floor mounded system, c/h side is fine, flow and return pipes on hw side all been checked and no blockage, ive flushed boiler no blocks, removed all traces of air, renewed primary pump near cylinder, and blown through coil no blockage. problem is when h/w is switched on. pipes to pump hot, pipe into cylinder hot, but from return to boiler from cylinder to boiler stone cold . this has been ongoing for 6 weeks had a so-called plumber out wanted mega bucks to power flush and fit odds and sods to a tune of £1400. any advice would be helpful thanks..

 

[secret squirrel]

are you 100% sure there are no air locks in the coil?

have you got a bleed valve on the primary flow/return? this will help let out air. My hot water cylinder is a pig to bleed the air out of.

Is there water entering the cwst?

if there is, there is a leak in the coil. Water may be discoloured or taste a bit odd to hot water or cold services run off tank.

 

[stecod7]

hi, thanks for reply. believe ive got all air out, there is a air valve on top of connections into cyinder which i have bled 6 times with pump off. i have no discolouration in water or odd taste. not sure about cwst? as im not a plumber . can you give me more info, thanks steve.

 

[oldplumber]

crack open the primary return fm the cyl to boiler when system fired up, can be messy but often only way to bleed out air lock, try flow in if still not working. Gravity primaries with no air release valves are a bu****

 

[stecod7]

i will give it a go. flow in is baking hot, if it was an airlock on return would the iron fitting coming out of cylinder feel hot,? all fittings from return by cylinder to boiler are stone cold. afraid im not up with technical lingo, are primaries the fittings into and from cyl. ps should have gone to plumbing school rather than carpentry@@ cheers.

 

[fireblade]

It could be the cold feed out of the little header tank blocked that would cause the heating not to have enough water in it

 

[helpsy]

Is the F&E tank overflowing???

 

[justlead1]

Hi. Is the boiler gas fired?
How far above the boiler is the cylinder situated ?
How far horizontally is the cylinder from the boiler?
What size are the flow and return from boiler to cylinder?

 

[stecod7]

slightly no blockage in pipe from header to connection near cyl. cheers for reply

thanks for reply. answers are gas boiler, 16ft on 2nd floor, 3mts horizontal. 22mm pipes. in some of my posts ive stated that ive disconnected most pipes from cyl to boiler and blown down coil and flushed boiler no blocks even from header tank to tconnections near cyl. heating fine but hw pipe hot to cyl but cold from base of cyl connections. hopefully its something simple im overlooking. no motorised valves but a secondary pump near cyl, renewed.

 

[rod A]

hi ,have you either a motorized valve on the return from cylinder or a cyltrol valve ? if so check they are open when calling for dhw ; Good luck Rod .

 

[stecod7]

no valves just 22mm flow and return pipes to boiler, with a 15mm pipe tee off to header tank, again no blockage in pipes,

 

[rod A]

HI, just checking facts 1,Gravity dhw but 22mm pipework? does not sound right with type of pipe runs you have. 2 you ,said that you have changed secondary pump, that would only circulate dhw around secondary cuicuit , if you have one, not primarys between boiler and cylinder.are you sure that there is not a pump on the primarys and one on c/h p.s I have seen lots of strange problems working for 20yrs as a ex trouble shooter for a british boiler manufacturer cheers Rod

 

[stecod7]

yes your right i have one pump near boiler for c/h, and apump near cylinder for h/w. today at 5pm i turned central heating and water on but left pump switched off by cylinder after 5mins of running i switched pump on at high setting, this seemed to heatthe return pipes for about 3mins then they went cold again. sorry if this doesnt make sense but my past posts will tell the story. thanks for your info.

 

[rod A]

hi again , if the vent/expandsion pipe comes off the top of the flow pipe and then rises up to the expandsion tank it is incorrectly positioned which will cause pumping over in header tank , air in system ,blocking of pipe work over a period. might also cause the problem with the return from the cylinder.hope this makes sense.!! good luck Rod

 

[david williams]

most people and a lot of plumbers will not know what a cytrol valve is

 

[stecod7]

hi, understand what your saying . my expansion pipe comes off flow pipe an rises up through to tank approx 4mts into loft. my system is 30plus years old and air has been a problem in rads until i recently flushed and bled system. hw side ive never had any probs until this christmas when boiler kept cutting out after a couple of minutes. but if i switched to heating and hw i got hot water. you may be right about air in system and im slowly shifting it .any tips , thanks steve.

 

[rod A]

Hi Steve, if you get stuck {only if} turn boiler off, reverse dhw pump so it pumps up return pipe pushing air up vent pipe to clear for five mins ,then fit back pump turn boiler back on ,should then be clear fingers x Rod

hi dave , cyltrol valve is a non - electrical thermostatic valve fitted to cylinder return pipe sensing temperture rise Like thermostat on radiator of car. cheers Rod [ now everbody knows]

 

[stecod7]

hi rod, thanks for reply, i left timer to come on this morning heating and hw also turned pump on highest setting, when boiler fired up heard a gurgle sound in coil and then return pipes became hot, after 7wks of fuffing around and some advice from you and others i might have cracked it. is it safe to leave pump on high? it is a eltech type.. thanks again.

 

[stevetheplumber]

0k to leave on high if its not pumping over id leave it for now and then try lowerig the setting when everythings settled and working

 

[rod A]

hi steve the plumber, good advise regard rod