CH blocked or pump failure?? HELP PLZ

[sh4tz]

HIYA,

A newbie looking for some assistance with my combi boiler...who's up for the challenge

So, i turned on my CH last week and it was noisey and only the 2 of the 5 radiators were getting warm. A week on..big problems!!

Every time i put the boiler on, after 30seconds or so it makes loud banging noise, wooshing sounds, and the boiler stops working (i think the thermostate light starts to flash). However, if i run the CH with the temperature on minimum (so that the boiler pump runs, but the fire doesnt ignite) the boiler runs fine albeit with no heat.

Another wierd thing, the CH flow out pipe leaves the boiler and enteres a Tee where it continues upstairs (22mm) and down to kitchen (15mm) pipe. When i can manage to get the boiler to run for a minute, the pipe only heats up the upward going 22mm, but not the downward facing 15mm. Also, there is a straight coupler midway on the 22mm pipe, the pipe after the coupler takes way longer to heat up than the 22mm pipe below the coupler and closest to the boiler exit.

What do you guys think?

P.S Discharge pipe drips a lot more outside, and also spits out water when the boiler makes lots of noises and switched off after loud banging.


HELP APPRECIATED!

 

[kevplumb]

1 boiler make / model

2 if the prv is spitting water the pressure is going to high and the boiler is overheating

3 would suspect expansion vessel

 

[sh4tz]

Wow that was such a quick reply!!

So although i will get lots of stick from people...the make is a Biasi and the model is a Riva Compact HE M96.

The boiler has kicked off about 5 times in total, after that i'd thought id just switch it off and get it fixed. In that time i also tried bleeding rads but no air, just water, came out. The pressure has fluctuated between 1 and 1.5 bar whilst i was trying to switch it on, not gone any lower than 1bar...and goes up and down as it wishes. i have not filled it further.
Thanks

 

[kevplumb]

first check the pump
undo the screw marked bleed and have a cloth handy
check the shaft is spinning
if not try using a narrow screwdriver and spin it View media item 17592

 

[sh4tz]

Ok, so took the large screw nut off and some water came out. However the shaft is spinning when i set the CH to the on position..looks like a small flat head screw in the hole spinning with a fan like thing around it i guess. Spinning fine as far as i can tell.

Again, i put the boiler on, the first 1foot of 22m pipe gets immensly hot, but the 15mm pipe off the Tee connection is stone cold, and the 22mm pipe after the straight coupler remains cold for a further few minutes until it catches up the the temp of the rest of the 22mm pipe. Seems so strange why it doesnt heat up at the same rate, it only a 1.5m stretch of pipe with a couple about 1.5ft into it.

 

[powell30]

Blocked or pump as kev has said.

What colour is the system water when you drain a little out of a rad? Plus silly but check all the isolation switches on the boiler are open and lastly check the diverter is working does your boiler work fine on hot water?

 

[sh4tz]

Blocked or pump as kev has said.

What colour is the system water when you drain a little out of a rad? Plus silly but check all the isolation switches on the boiler are open and lastly check the diverter is working does your boiler work fine on hot water?

Hi mate, water was very clear with some white clouding in it. All isolation switches ( i assume the small lever taps on the pipes going in and out of the boiler) are open. Hot water works perfect.

No sure how to check divertor..is it easy? I am a very good d.i.y'er so if its doable, i can usually do it.

Regards

 

[travis2000]

sounds blocked to me, I had similar problems and it turned out there was rock like deposits in the plastic microbore (mainly at the bends after the T)

 

[sh4tz]

sounds blocked to me, I had similar problems and it turned out there was rock like deposits in the plastic microbore (mainly at the bends after the T)

How did you sort the blockage out out Travis2000?? System is only 3yrs old so is this still a likely problem?

Do other guys on the forum tend to agree.

Will Fernox f3 cleaner help?

 

[kevplumb]

is the hot water working

 

[travis2000]

I'm no plumber buddy but handy at diy. Unfortunatly I ended up having to replace the pipes that where blocked. I literally went in from the trap and ran a new pipe from the T junction to the rad leg. Had to cut into the stud wall a little but it wasn't that bad at all. Nothing else would work! Tried fernox etc
Like I said I'm far from an expert and these other guys will prob help more

 

[sh4tz]

is the hot water working

Hot water is working fine.

 

[kevplumb]

wish you had said that in the first place

could well be clogged/ sticking /shot diverter valve

 

[sh4tz]

wish you had said that in the first place

could well be clogged/ sticking /shot diverter valve

Sorry Kev, yeh water works fine. I was thinking that if the water isnt circulating properly, the water in the immediate area of the boiler is heating up too much and tripping the thermostate due to over heat. The excess steam and pressure is then spat out through the discharge pipe...i could be totally wrong.

This divertor valve...how can i check its ok...ot does it need a professional?

 

[sh4tz]

Hi everyone,

so had a check and the pump is spinning fine, and also the pressure vessel is pressured fine too. The CH system pressure remains between 1bar and 1.5bar, the short 22mm pipe coming straight out of the boiler heats up incredibly, however after the Tee juntion, one of the Tee 15mm pipe remains stone cold, and the oher Tee 22mm going upstair heats up slowly, however 1ft up there is a straight coupler and the pipe above that coupler takes even lonnger to heat up.

The CH keeps running fine, just the pipes and rads are not heating up. There is white powder build up on the Tee and on the straight coupler, as well as quite a lot on the thin copper pipe going into the pressure vessel.

Water i have extracted from radiator is clean bt very cloudy..is this ok?