Banging Thorne Apollo Boiler!

[croydoncorgi]

When the 3-port valve actuates, the manual lever on the side is SUPPOSED to be loose!!! It shows that it's working!

How did you manage to change the pump without subsequently bleeding air out of the rads and the rest of the system? Even if you did not need to drain the system, a little air would still have got in, in the body of the new pump. Making sure there's no air in a CH system is the usual first step, whatever the problem.

Have you found the small F&E tank which fills up the CH system? (NOT the cold water storage tank which supplies the hot water cylinder and possibly the cold taps in the bathroom.) Alternatively, does your hot water cylinder have on it anywhere the word 'Primatic' (clutching at straws here!!)

 

[Rookery]

OK the latest developments:

1) Bled the rads with system turned off. Virtually no air hissed out and water was clear.

2) Turned on the CH and HW and boiler worked fine. Of the 3 rads the one in the bathroom heated up fine although the other two (living and bedroom) stayed stone cold. However the pipes up to the cold rads did warm up but weren't as hot as the one in the bathroom. (Before anyone asks yes they were both turned on.) Bled rads again and small hiss from bedroom rad but nothing more.

2) After 40 mins (usually how long it takes to get hot water coincidentally) the boiler starts playing up again turning itself on and off every 30 secs or so. However less banging now it's warm than when it was cold and turning itself on and off. Interestingly the other 2 rads now start to warm up albeit very slowly as boiler is only working intermittingly.

3) I'd hazard a guess that if I let the HW go cold for a day and then turn the systems back on again it'd work fine(-ish) for 40 mins before starting to play up again.

Some additional info: I have an immersion heater. Also have a "Honeywell 3 position Y-Plan Sundial" diverter valve set to Auto.

With this info can anyone pinpoint what the problem might be? Doesn't look like a new boiler does it?

 

[Rookery]

Corgi strangely when I posted my last response your reply wasnt there even though mine was done 2 hours later.

In response to your questions no the plumber didnt bleed anything after fitting the new pump. Your point reduces my already minimal faith in him even further.

Is there anything in what I wrote that allows you to pinpoint what exactly is happening? I think it's the 3 port valve.

 

[PEDANTICVINDICTIVEMAN]

Well I've heard of some funny goings on, but banging a boiler is something else, hope your using protection.

 

[Rookery]

Thanks for the follow up posts people....NOT. Talk about leaving people hanging in the wind.

By way of follow up for anyone else out there who may be experiencing the same problems the solution was the 3 point valve. Fixed that and it worked.

 

[kevplumb]

try locking the three port valve mid position it sounds like a curculation problem

which was suggested on the tenth

 

[croydoncorgi]

Yup .... I thought we'd covered that already...
Also, a nice thing about 3-port valves is that they cannot prevent flow altogether: either one or both ports will be open all the time. So if you get (apparently) problems with circulation which cause the boiler to overheat, it's quite unlikely to be ONLY to do with a defective 3-port!

What was in fact wrong with yours? Unless an outlet was physically blocked, I can't see how it could match with your other symptoms.

 

[Rookery]

Croydon thanks for replying. I think you may have hit the nail on the head. The situation right now:

1) CH comes on (HW turned off) and doesnt fall over like it used to. Rads start to warm up. Improvement on before.

2) After 10/15 mins boiler starts to cycle every 30 secs or so. Rads are red hot.

I have 3 rads and this is an Apollo 15/30 boiler. Also there is a kink in the pipework to the A port on the valve which possibly reduces the flow of water to 8mm. The plumber seems to think now we have changed the pump and valve the system is a whole lot more efficient and thats why the bolier is overheating a lot quicker.

I take this with a pinch of salt as it never used to cycle so often and worked fine with all rads hot (but not as hot as now).

Apparantly this pipe is meant to be 22mm (like the pipes in the AB and B ports) but it is only the standard diameter. The HW still works fine.

Can anyone suggest what else might be wrong?

 

[kevplumb]

I have 3 rads and this is an Apollo 15/30 boiler. Also there is a kink in the pipework to the A port on the valve which possibly reduces the flow of water to 8mm. The plumber seems to think now we have changed the pump and valve the system is a whole lot more efficient and thats why the bolier is overheating a lot quicker.

pleeeesee tell me this is a wind up

 

[Rookery]

Kev this aint no rise mate. This dont sound good. Whats your thoughts then?

 

[kevplumb]

so you have a 22mm pipe reduced to 8mm and cant understand why your boiler cant shift the heat on the heating side

sort the pipework
your plumber aint a heating guy i take it

just to be smug i did tell you it was a flow problem (as did everybody else)
we just couldnt figure out why if you had mentioned this in the first place you would be sorted by now mate

we try but we are only looking at a monitor

 

[Rookery]

No it's not a 22mm pipe. It's the other more standard size that connects into port A on the valve. 15mm is it? First question: should this is be 22mm as well? (This was already there - nothing to do with us).

Secondly considering the symptoms I've described ie. fine for 10 mins then cycling on the boiler, if I were to mend the pipe you think it'd be OK?

Thirdly yes he profeses to be a heating specialist!

 

[kevplumb]

i would go with 22 at least to the first rad you need to lose the heat that the boiler is putting in
ie boiler puts 10 kw in rads lose 5 its going to get warm and cycle or overheat
pipe sizing comes into this you can only lose so much heat for a certain bore of pipe

 

[Rookery]

Thing is it's always worked up till now with this thinner pipe. Must be the kink thats doing it then as I expect in the first 10 mins enough heat is lost and therefore it doesnt cycle.

The plumber says this is normal behaviour for the boiler. Tosh right?

Could there be anything else causing this?

Thanks for help in advance.

 

[kevplumb]

first 10 mins the system is cold so could well be

as for your next point right

as i said earlier could be crud in the system if you have a flow restriction it will tend to collect there