Central Heating pump orientation

[Softus]

Happy New Year Anastasia!

The reason for my question, in case it was too cryptic, is that the fact the pipe 4 is cooler is not enough to tell us that you have the pump fitted the right way round, because, with the pump on and pumping down, pipe 4 always will be cooler.

Therefore, what would be interesting would be to prevent the pump running (by disconnecting its electrical supply), run the boiler, and feel which pipe is hotter then. If it's on the left, then the pump is on the return side and should be fitted pumping up.

From the images it looks to me as though the pipe from the left side of the boiler goes to a high primary connection on the cylinder. It would be normal for this to be the "flow", with the "return" being lower down. This is not a hard and fast rule, because it's valid, albeit rare, to connect the boiler flow to the lower primary cylinder connection, but that's not your scenario either, from what I can see.

However, I can't see the lower primary connection from your images. Hmm, but it looks as though it's connected to one of the outlets from the 3-port MZV. This is a better indication that the pump ought to pump down, but I haven't seen anything conclusive yet. Perhaps I'm missing something?

 

[JohnD]

Get grandma back up in the loft to take some pics of the tanks and pipes.

 

[Anastasia]

Bab :

In answer to your questions:-

The header tank is sat on a platform standing about 2/3 feet above the joists, therefore increasing the head.

The pipe coming out of the small tank is 22mm and there is no pipe 'Teed' off it.

I flushed all the radiators by removing each one in turn and flushing mains water through them till it ran clean. I then put some B & Q flushing fluid into the header tank and let it run for a few days, after which I drained the system and re-filled with some inhibitor in the header tank.

Yes I have adjusted the balancing valve. A Gas Service man that called told me I should have this just open not fully open, but it doesn't seem to make any difference to the banging.

How Do I de-scale the boiler other than adding something to the header tank.?

I currently have the boiler thermostat set on the low setting, and the problem still persists. If I change to the high setting, the pump is louder all the time, and as it is on the wall to my bedroom I do not want to leave it set on high all the time. I believe the banging still occurs on the high setting.

Thanks all of you for your thoughts. Please keep them coming.

 

[bab]

hey I'm impressesd. don't care what they say about flushing machines u cant beat takin the rads off an blastin em through.Yes the ballancing valve should only just be open. If its open to much u hav hot water from the boiler going straight back into the boiler not helping to keep the boiler from ketteling. if you have put inhibiter in the system after u flushed it u should drain it down again(uhh) sorry & add a ltr off descaler & run for the maximum the tub says u can. Then drain & flush & refill adding inhibiter.If u find the boiler is better even after aweek still leave it in. U may find u have to do this again in a couple of years.Also when did u last hav it serviced. It looks open flue & if the heatexchanger canckers up as these boilers r prone to they can spill fumes. I once went to 1 of these boilers & the heatexchanger was so bad with green canker the flames went up the inside of the casing & melted the terminals off the over heat stat.Not a bad idea havin it serviced before u do any thing.

 

[Anastasia]

Bab :

I had the boiler serviced by that Gas Service Man I mentioned earlier.

I will do as you suggest, but just to clarify one point : Do I add the de-scaler in to the header tank after draining some water out, or am I supposed to add it to the boiler somewhere else. If so where.

 

[bab]

Sorry some times get carried away, If u have inhibiter in at the present time u should drain down completly. Add the descaler into the header tank then refill the whole system.Then run the system as normal heating & hot water on .It will say on the tub of descaler how long u can leave it in. The longest u r allowed is best . (could be a month)Then drain down again .When filling 4 the last time add inhibiter into the header tank. If at the present time u do not have inhibiter in u only need to drop a couple of rads ,put the descaler in the tank then refill. As for the noise u have at the moment have u bled any air out of the small air vent on the left hand side of the 3port valve. Try running the system with the pump on max speed ,bypass valve shut on heating only 4 1 hr. If your clock wont let u do heating only turn your cylinderstat down on the bottom front of the cylinder.

 

[Anastasia]

Bab :

As for the noise u have at the moment have u bled any air out of the small air vent on the left hand side of the 3port valve.

Yes, but I get very little if any air out of there.

This suggestion for running the pump on max with the by-pass closed. What is the object of this. By the way I am trying it now. As you are in Lancashire yourself please ignore any loud explosions you may hear in about an hour.

Thanks for all your comments. Your attention is warming even if my central heating isn't

 

[bab]

If the boiler needs decaling the noise of kettling,& banging should de be a different noise than if the pump is . When u refill up a system the water in there is full off oxegen. This in its self will make the pump apear loud as it pumps liquid far better than air bubbles.Also if the bypas is shut & its only go'in around the rads it will help to remove any trapped bubbles & eliminate them .by the way The automatic air vent on the top left of the boiler that the engineer changed,is the little cap on the top loose as it should be. No big bangs in Preston yet.

 

[Anastasia]

Bab

Don't know if you are still celebrating the New Year but your first line of your last posting lost me.

I have actually removed the black plastic cap from the air vent, the theory being that I thought maybe the cap was stopping the system venting. Will it be Ok.

I am only in Lostock Hall so I am surprised my system isn't waking you up as well at 6 o clock in the morning.

 

[bab]

Bab

The black cap is best left on cause if the bottle vent fails its ur only way to stop the water coming out.Just leave it loose. Dont foget to open up the bypass a little or the over run has no where to pump. & turn up the cylinder stat again.I do think ya boiler needs a good descaling but ya bypass curcuits a tad small to.has it run any better. I,m near to garstang so shouldnt here it any way. Andrew.

 

[Anastasia]

Bab (Andrew)

I will let you know how it goes in the morning. I have reset everything back to the way it was and put the black cap back on loose as you suggested. (Did you know you had a Pub in Garstang which was in the guiness book of records for the shortest name The XL. Can't remember what it is called now. On the corner heading out to Pilling. Chris