Upstairs, and 2 downstairs rads working intermittently

[TeeKay10]

Hi all,

I have had a look through and think I may have a solution to the prob but just wanted to check all other possibles first if you can please help!

Just fired up the heating for the first time since last winter and all of the upstairs rads (apart from the towel one in the en suite??) and 2 of the downstairs ones only come on occasionally. It's possible that they are only on when the hot water is on, but what with work etc, I haven't had time to check with it on and off.

I have an Ideal Classic FF30 boiler, all rads have TRV's that are on, there's a temperature control jobby in the hall (very technical!) and a ACL mid position valve in the airing cupboard. There's an F&E tank plus the big tank in the loft too.

From reading on here am I right in thinking it's poss that the ACL valve has gone divvy? It was installed in 1998 when the house was built, as was the boiler etc. The system was cleaned and flushed earlier this year as well, just FYI so it shouldn't be a sludge prob.

Also, I did notice in the summer that 1 of the upstairs rads (that pesky towel one!) and one downstairs were sometimes on, even though the CH switch on the timer was off and the Thermo in the hall was off???

Plus occasionally there is warm water running through the basin and bath taps - although not for long.

Any info and help welcomed - I'm a mere female so be gentle, lol!

Although I'm not afraid to 'have a go' where ness (I've done renovations and fitted basic kitchen and bathroom plumbing/elecs in the past)

Ta muchly - fab site!

 

[JohnD]

turn off the hot ones, and see if the cold ones then warm up.

How hot is the hot water?

How cold is the cold water?

Feel all three of the pipes on the three way valve. When the heating has been off for a few hours, but the HW is on; and vice-versa. How hot are they?

 

[Armo74]

It's possible that the pins are stuck down on the TRV's on the rads that don't heat up. I hope you don't have a TRV in the same room as your wall stat as you say you have them on every rad. The rads that heat up when the central heating is not on will probably be bypass rads to dissipate eccess heat when only the hot water is on(perfectly normal). Although not a good idea to have TRV's on them either if they are, but there is usually only 1 bypass rad.

 

[JohnD]

all of the upstairs rads (apart from the towel one in the en suite??) and 2 of the downstairs ones only come on occasionally.

this will not be stuck pins.

 

[Armo74]

all of the upstairs rads (apart from the towel one in the en suite??) and 2 of the downstairs ones only come on occasionally.

this will not be stuck pins.

Correct. Apologies, that will teach me to read the post correctly in future

 

[TeeKay10]

Hi and thanks for the replies so far.

I have turned off the hot rads and all but one (the main bathroom) of the cold ones have come on and are hot.

The pipes to the TRV's of the ones I turned off for testing purposes are cold if that helps?

The hot water in the taps is hot (not scalding level though as I turned down the dial on the cylinder) and the cold is cold (apart from when it sometimes comes through warm at first lol!)

I also had a feel of the 3 way pipes whilst the heating is on and the pipe to the left of the 'T' (that comes from/to the cylinder tank pipework) is warm (as in almost graspable without burning) but not hot. The pipe actually coming in/out of the cylinder is very very hot and where it joins the pipe that goes to just a stop end, that is also very very hot. Then it goes off to the warm pipe into the valve.

Does that make sense?!

The cylinder itself is actually turned off at the power switch as it needs a new thermo and I haven't got round to fitting one yet.

The other 2 pipes in the 'T' formation (to the right and the down) are too hot to grasp.

The valve does move as it should do to the 'M' position when CH and HW are on and to the 'H' pos when just CH is on.

Haven't checked for just the water on yet as it's a bit nippy today so want the heating on! Will look tmw as I'm off so have more time.

Any clues by these details please?

 

[Hugh Jaleak]

Hot water from cold taps usually results from the hot and cold pipes running tight together, some heat transfer goes into the cold supply giving warm water at the taps initially until fresh cold water gets through.

Power switch to immersion you can leave off. Cheaper to heat the cylinder using the boiler, the immersion is fitted for backup if the boiler breaks down. Cylinder stat needs to be set at about 60C to prevent Legionella bacteria forming.

Towel rail could be connected to the HW circuit rather than the heating, this is to allow warm towels in summer months when heating is off. ACL valve from your description sounds like its working as it should, cold rads could be either a balancing issue or airlocked. Try bleeding cold rads (with heating OFF) in case there's trapped air, if none then i'd turn off all the rads apart from one cold rad and see if it heats up. If it does, then turn cold rads on one at a time, in theory the pump should be putting its full effort into that leg of the system and push through any trapped air.

If the cold rads then work, but go cold again once rest are turned on again then may need to balance the system. See boiler and CH FAQ's no. 5 for a link on how to do this.

 

[JohnD]

"I have turned off the hot rads and all but one (the main bathroom) of the cold ones have come on and are hot."

This reinforces my belief that you need to balance your rads, and lack of balacing is the cause of your prob.

Turn the heating off and run the boiler on HW only to see if the bathrrom rad warms up, if not, then does it have a TRV? It is probably stuck shut, especially is someone screwed it down tight during the summer.

The slightly-warm pipe on the 3-port valve probably means is is leaking slightly down the "closed" pipe, or it might just be conducted heat. If the warmth exends a couple of metres then is it wear and leakage. It will cost you wasted energy in the summer but is not significant in winter.

As for the cylinder, Legionella dies within a few hours at 55C, and does not multiply above 50C

So you do not need to heat the cyl to 60C, which I find rather too hot.

There are vague stories about copper pipes and cylinders having disinfectant properties.

If you have a cold water tank in the loft which is not insulated, then in summer it may get warm enough for bacteria to thrive (that's the main reason why loft tanks are meant to be well-insulated. Unlike pipes, they take a long time to freeze). So a shower blending hot water with cold from the tank is more risky, especialy in summer.

 

[TeeKay10]

Thanks again - very informative!

Bathroom rad does have a TRV and I noticed earlier that the pipe going to it is hot so I'm guessing the TRV is kaput like you suggested. (Rad's been bled so it's not that) It is a 15 year old system and I had to change 2 other TRV's last year so I guess they are all on the way out. I'll flick off one of the ones on a working rad and swap them to check.

Cyl has a jacket on (and tank in loft has some insulation on top of the lid!) and the water is set to approx 50 degrees.

Thanks again, will have a play with the HW tmw and see what's what