Power flush for circulation problem

[George J]

Hi,

I have a problem of boiler kettling and noisy pump = circulation problem.

I tried a combined descaler/inhibitor some 2/3 years ago but the problem has returned.

Is there a DIY way to power flush the system?

 

[ArtfulBodger]

Hire out a power flushing machine for about £50 and then DIY it

 

[bab]

when u descale a boiler u never know how much u left in there. If ur gona do it retry a good descaler on its own.& leave it in as long as its permitted. I think sentenial x200 can be left in long term but u would have to check on that. If theres no ballance valve on the flow to the cylinder is there 1 on the return on the primary circuit out of the cylinder. If not fit one while its drained.

 

[George J]

Bab,

Please excuse my ignorance but can you confirm that when we're talking about a balance valve we're referring to a by-pass valve. Mine is fitted to the 22mm primary flow to the cyl., 15mm teed off between pump and diverter valve, and goes back to return pipe. It uses a gate valve as opposed to the stopcock. Is there any advantage in removing gate valve and fitting an auto balance valve?

ArtfulBodger,

Before I hire one I'd like to find out whats involved. I'd be very grateful for any advice. Is it a practical proposition for a practically able DIYer? And what should I look out for?

 

[bab]

The pipe with the gate valve going from between pump & midposition valve is the by-pass with a balance valve on it. u should also have a balance valve on the flow or return on the cylinder htg pipes just so u can slow down the water going trough the coil to stop the boiler cyling in summer & to direct more of the flow of water to the rads in winter.

 

[George J]

So my gate valve is being used as a balance valve?

If we ignore the gate valve there is not another valve of any sort, apart from diverter, on the flow or return to the cyl. coil.

I can see the advantage of restricting the flow during winter = rads get better priority. But not sure why I should want to stop boiler cyling in summer. Thats assuming I have controller set to Summer = HW only and Winter = CH&HW.

 

[bab]

cycling is when the water coming back into the return on the boiler almost as hot as it left.It wastes gas if its firing up for 1min every other min. depending on what the set up is its good to turn ya boiler & pump speed down a bit in summer as long as u remember to turn it back up in winter.

 

[George J]

Makes sense. So I need to install a balance valve. What constitutes a balance valve? Is it simpy a gate valve or something more technically advanced? I presume it should be positioned between diverter and cylinder coil and preferably on the flow.

 

[bab]

Strickley speaking it should be a lockshield head gate valve to stop it being tamperd with when set. Most use standard gate valve,I do but remove red wheel head & tie it on the pipe with a string. Wants to be open about 1 1/2 revs.Can be onflow or return or return is best if you need to change cylinder at a later date u might not have to drain down. i always put one on the htg outlet on the zone valve so u can remove those as well without a drain down PS . When buying the gate valves ask for British Standard valves. Beta quality when u need it.

 

[George J]

Excellent.

Full of optimism now. Will be hiring a powerflusher and also doing what you suggest. Sure it will help keep the wife and kids off my case. If it doesn't then I might use the powerflusher on them.

Many thanks bab.

Have bookmarked this really helpful site.

 

[bab]

Good glad to help .Gona go back to the tools 2morow so this 'l be only a bit a fun at night. Would luv to do this 4 money .beats gettin dirty.

 

[meldrew's_mate]

I have a problem of boiler kettling and noisy pump = circulation problem.

It's nice to see you two getting on so well, but don't forget the original post

Bab has made perfectly relevant points which will make your system work better, but only after you have cleaned it properly. I can only add that you check the cold feed to the inlet of the pump (usually a 15mm feed from the loft tank) is clear, they sometimes block and the effect is poor circulation. Also dismantle the pump and clean this too, it'll need to be out if you connect a power-flusher properly so why not do it now?

Finally, when power-flushing use good quality chemicals or you may be throwing away good money removing only a small percentage of the c.r.a.p. in there

 

[George J]

You all obviously get pleasure from helping folk. I find it's often the money thing that gets in the way and halves the pleasure. Then on the other hand it's often the only pleasure to be had from some jobs. If it were possible to help folk without charging AND without getting ya hands dirty AND still have food on ya table then that would do me.

Here endith the sermon.

I'm a master locksmith and will definitely be returning the favour on the security forum once I get the central heating sorted. So sometime in the future you will get the favour returned maybe even directly by me.