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Noisy central heating
Northy - 7/11/06 at 01:06 PM

Hi guys, hope someone can help.

Every morning when the central heating kicks in it is very noisy, the noise is coming from the airing cupboard and sounds a bit like a pump that is catching as it spins, does that make sense?

The noise gets gradually quieter until its gone as the system heats up.

Any ideas? Is it fubar'ed?

Cheers,

G


Schrodinger - 7/11/06 at 01:15 PM

Hi Graham
It sounds like there could be air in the system. I would check to make sure that the ball cock in the header tank is not stuck closed with no water in the tank and bleed the system,


owelly - 7/11/06 at 01:18 PM

sounds like the pump is telling you to save up for a new one!!
What speed setting is it on? Try turning it down.


Northy - 7/11/06 at 01:19 PM

2 questions:

What does the pump look like!

How do I bleed the system?!

Cheers

G


Aboardman - 7/11/06 at 01:30 PM

pump is normally about 4" across with 2 pipes coming into, and 1 electric cable.

here is a site about bleeding the radiators.

http://www.diydata.com/problem/central_heating/bleed.htm

[Edited on 7/11/06 by Aboardman]


StevieB - 7/11/06 at 02:06 PM

Pump will look like a plant pot shaped object stuck onto the pipes somewhere near your boiler/tank. They're not too expensive to replace (£60ish).

Bleeding the system is quite easy - just do a bit of web research first.

I got used to all this stuff when I bought my new house (and I mean new - only 6 years old) and the CH is proper f****d. Bad design means all of the microbore piping is clogged up and will need replacing (according to a neighbour with a similar problem who's a plumber).

I solved it by wearing a jumper until summer came. Now that Mrs StevieB has 7 months left on the build time for baby StevieB, I need to get it properly fixed.

Where's my big hammer...


Northy - 7/11/06 at 02:36 PM

Thanks for the replies so far guys.

I'm just trying to sort out what type of system we have. We have a boiler in a cupboard in the kitchen and also a large water tank with a jacket fitted in the airing cupboard.

Does this mean it is not a sealed system? Should there be a header tank for the water tank in the loft?

Last time I was in the loft all the tanks had water in and were ok. Do I just bleed the radiators and let it top itself up?

Cheers,

G


StevieB - 7/11/06 at 02:46 PM

First, shut off the boiler.

To bleed the system, you need to turn off the water supply to your system (if it's a tank in the loft, just use a piece of wood to prop the float up).

Then find the outlets on the system (ground floor, little nozzles on the return end of the radiators).

Attach a length of hose and get plenty of towels (I use a watering can to drain into and pour it down the toilet).

Then, open the valve and water will start flowing. Open the bleed vents on upstairs rads to let air in and the flow will be better. Then just keep going around the house until the system is completely dry, and you can do pretty much what you want (remove/inspect/replace the pump etc.)

You'll be amazed by the amount of crappy stuff that comes out of the system!

Whe you refill, don't forget to chuck some inhibiter in to protect from rust (£20 from Plumbworld).

Might be worth running some system flush through as well while you're at it.

[Edited on 7/11/06 by StevieB]


Aboardman - 7/11/06 at 03:02 PM

quote:
Originally posted by StevieB
First, shut off the boiler.

To bleed the system, you need to turn off the water supply to your system (if it's a tank in the loft, just use a piece of wood to prop the float up).

Then find the outlets on the system (ground floor, little nozzles on the return end of the radiators).

Attach a length of hose and get plenty of towels (I use a watering can to drain into and pour it down the toilet).

Then, open the valve and water will start flowing. Open the bleed vents on upstairs rads to let air in and the flow will be better. Then just keep going around the house until the system is completely dry, and you can do pretty much what you want (remove/inspect/replace the pump etc.)

You'll be amazed by the amount of crappy stuff that comes out of the system!

Whe you refill, don't forget to chuck some inhibiter in to protect from rust (£20 from Plumbworld).

Might be worth running some system flush through as well while you're at it.

[Edited on 7/11/06 by StevieB]


what you have explained here is how to drain the system this is required if you have to change the pump unless the the pumps is isolated with valves either side of it.

to bleed the system have the heating going, and then go around each radiator and use a bleed key/screwdriver at the top valve of the radiator. you will need a towel unless you want to spray yourself and walls with dirty water.


Peteff - 7/11/06 at 04:03 PM

Don't use a towel, get an old rag or you will get you earhole chewed . If the pump is sticking undo the blank in the middle of the pump top with a large screwdriver and then turn the spindle in the centre with a small screwdriver. I have to do this occasionally if the pump isn't used for a few months. Don't panic if a little water gets out, it soon stops. Grundfos are good pumps and are about £60-£70 as mentioned above.


Northy - 7/11/06 at 08:38 PM

Right, I've had a look.

Got no air out of the radiators. The pump is a myson compact cp53. The speed was set flat out (3) so I've set that to 2. It does sound a bit noisy when it runs, I wonder if the bearings are on there way out?

When I do th emanual start spin thingy on it, it doesn't spin really free, it sort of grinds a bit. Is that right?

Cheers,

G


Northy - 7/11/06 at 08:43 PM

Almost forgot, I tried turning the pump onto speed 1 and it would not turn, just buzzed a bit. I guess this is a sign the bearings are fubar'ed?

Cheers,

G


JoelP - 7/11/06 at 09:08 PM

certainly sounds likely graham, though there is still the possibility that it is just a lot of smeg caught in it. Start by draining it and having a look in. As someone said, it might be worth getting it flushed out whilst you're at it.


owelly - 7/11/06 at 09:17 PM

As I said, new pump time!!
If you buy a cheap one (£15ish) you can expect to buy another one in a few months time! You may be lucky and get one that will last a full year but I recommend gettinga good one. Grundfoss (as mentioned) are good units. Goto a reputable plumbers place and look to spending over £45 minimum.
I suspect the mech seal has started to break-up and jas let water into the bearings.


Guinness - 7/11/06 at 09:17 PM

Our pump started to go this time last year. After a summer of inactivity it sort of rusted up a bit. My mate who's a plumber explained that little bits of rust can jam the blades, so you have to bump start it by unscrewing the hex bolt in the middle a bit, pulling it out a bit and turning it. This worked for a while but we got sick of it so changed the pump. Not too difficult, 3 wires, two really big nuts to undo.

(P.S. I am completely unqualified to offer advice about this, so don't blame me if thats wrong)

We are currently redecorating the living room and dining room and have taken the rads off to flush them through and decorate behind them.

Mike