Unblocking a Heat Exchanger on Worcester 532i combi?

[JulianC]

(I'm no expert but will do a lot of research and attempt most things if it will save me money and is legal to do myself)

I moved into this house 1 year ago, but I think the boiler (Worcester 532i) is about 8-9 years old.

At the weekend I moved a radiator (Someone had mounted it very high on the wall and I cut down the pipes and moved it down so I could fit a Dado rail at 3 feet)

I didn’t see any sludge when I was draining the system but a small amount did leak out of the radiator when I moved it (this radiator looks older than all the others on the system). (really wish now I had flushed out the radiator!)

I don’t know if there was inhibitor in the system but the water did smell quite chemically and was clear, so I'm thinking there was.

I re-pressurised the heating system and bled the radiators of all air and ran the heating and all the radiators got hot quickly and no Leaks from the one I moved J


The problems was noticed when I was trying to run a bath, The water got hot but after about 15 seconds went cold again.

We have had this problem intermittently since moving in but used to happened sometimes after about 5 mins running the bath tap, so has got a lot worse!

I took a look at the boiler with the tap running and the temp gauge just keeps climbing to 109 and then I hear some value click and the flame goes out and the temp slowly starts to fall and the water goes cold. I cannot see any water coming out of the overflow pipe outside.

From doing some googling I think that sludge from moving the radiator has blocked up the heat exchanger (but which one?)

I have ordered some sentinel x800 to see if this clears it out of the heat exchanger.

I guess my questions to the forum are:

Do they think it is the heat exchanger or something else?

Is there a chance the Sentinel x800 will clean the heat exchanger? I have seen on forums others having some success with this. I know because I have an aluminium heat Exchanger I should limit the time of the x800 in the system to 3 hours (But if the exchanger if buggered anyway, might as well try)

For £55 should I fit a Magnaclean first? So that sludge loosened by the Sentinel x800 is captured in it before getting to the Boiler?


I don’t want to pay £500 for a pressure flush of the system (I wish I earned £100 an hour!), but is it worth taking off each radiator in turn and running a hose or pressure washer through them?


If that doesn’t work will I need a:
(I would get a local engineer to fit these parts if I need them)

£50 odd quid Plate heat exchanger?

Or a £400 odd quid main heat exchanger?

Any ideas would be great.

I'm on a tight budget as we have a baby due in a few weeks ,

So will be trying to do must stuff myself to avoid the high labour costs.

Thanks

 

[Agile]

It is likely to be the secondary heat exchanger.

Those almost always have to be removed to clean them.

Plenty of threads on how to clean them.

On some boilers you need to be gas safe registered to safely access them.

Tony

 

[bazdaman]

I would be looking elsewhre on that model, temp should not get to 109 c even with a blocked plate

 

[JulianC]

well I ran my central heating flat out for 2 hours tonight and it seems to have sorted the problem out for now
maybe it was just an air lock or it cleared some crude out.

I still might flush it with cleaner when I get a change at the weekend.

 

[Paul Barker]

Some Worcester 's such as the R40 a predecesor to the cdi and possibly the cdi may do it. They fault like this when the pump fails. Because you are running hot water the instruction to the burner is to run at max. Temp control feedback is not able to predict pump failure it is looking for a gradual change in temp. So the burner is cut much too late. It is really a design fault. So primary temp goes way over high, much more high than in the other scenario of when the plate is blocked.

So might still be plate, but could well be pump.

 

[snes]

Welcome back, Paul, haven't seen you in the open forums for a long time.

You used to be a Buderus man, if I remember, what are you fitting now?

 

[petit_pablo]

Plate is most likely particularly if the heatings working fine. I've seen many a worcester hit over 100c when blocked.

 

[Paul Barker]

Welcome back, Paul, haven't seen you in the open forums for a long time.

You used to be a Buderus man, if I remember, what are you fitting now?

Still fix Buderus but not tribal about what boiler I recommend.

 

[JulianC]

Yeah I think I need a Magnaclean! and a power Flush

This is some water I pumped out of the top of my towel radiator so I could put the Inhibitor back in the system. (I had to pump it out because the bottom value was seized when I tried to get it off)

There is loads of ferrous partials in it.

That get stuck to the magnet.

I'm thinking that the people who owned the house before drained the system to add the towel radiator and didn't add any inhibitor back to the system.

Since disturbing the rust/sludge again the hot water problem has come back

 

[Agile]

I don't see anyone who has advised you to get a power flush!

 

[Paul Barker]

Yeah I think I need a Magnaclean! and a power Flush

This is some water I pumped out of the top of my towel radiator so I could put the Inhibitor back in the system. (I had to pump it out because the bottom value was seized when I tried to get it off)

There is loads of ferrous partials in it.

That get stuck to the magnet.

I'm thinking that the people who owned the house before drained the system to add the towel radiator and didn't add any inhibitor back to the system.

Since disturbing the rust/sludge again the hot water problem has come back

don't beat your self up about it. clean plate or renew it and you'll have as long again.
Going forward, prevent airation of system water with frequent refilling, dripping prv's flat expansion vessel undealt with system leaks. Keep a system sealed with none of aforementioned problems. No need for inhibitor. conversely if you put inhibitor in, and have any of a bove issues, you just poured your money down the drain anyway.