SOT: DIY FAIL: CH Conundrum - Fixed (?)

[Another John]

The "(?)" in the Subject is because I try not to tempt fate. The "SOT" is because this is long, and most people won't be bothered about reading it, but I _did_ say I'd come back and report! I've divided it into 5 Parts for your convenience :-)

Part 1 - History

Some may remember my pleas for advice on 22 April which began:

- About four weeks ago I noticed that our radiators were taking longer

and longer to warm up.

- I decided (for no reason other than it had never been done for 7

years) that the system was probably gunged up, and needed draining and refilling.

- Most of our radiators are at least 30 years old; it is a microbore

system (dammit); inhibitor was put in when the system was last filled, 7 years ago.

- The boiler has not been serviced since it was installed in 2008, and

neither has the system as a whole, which was renovated at that time. For one thing, service fees seem extraordinarily high, for another I am (or was) a believer in "if it ain't broke ..."

Part 2 - What happened next

My request for advice here was followed by a very useful sequence of messages from some of you, experts in this field of CH, which was both educational and encouraging for me. The upshot about a week later was that the problem might be the pump, and I ought to start by renewing that.

Despite the cheers and "Go-on!"s from the sidelines I chickened out: I decided to get a plumber/heating engineer in, on the basis that what he could do in about 15 minutes, would take me hours, and I'd probably c*ck it up.

In addition, I figured that a professional would be able to diagnose the overall fault (If it wasn't actually the pump), and do something about it (e.g. flush the system; change the 3-way; check out the boiler .... it goes on, as you well know).

I could not get a local man: plumbers/engineers were too busy and/or reluctant to do this. The last (recommended) chap I tried said that (a) it probably wasn't the pump, (b) if the system has inhibitor, it shouldn't be gunge and (c) it was probably the boiler, and I ought to contact Glow Worm themselves, and pay for a service and/or "one-off fix". (Interestingly, the very first chap I tried had also recommended one of the big boys (British Gas).)

I explained that I'd always hoped for a local bloke, because I'd be supporting a local, and wouldn't be paying vast amount of money to a large faceless company blah blah blah. He responded by giving a "Big Up" to GW, saying that a local wouldn't be much cheaper, and at least I'd have GW's own people on the job.

I rang Glow Worm. Annual service is ?96 (if you see a squiggle there instead of a pound sign -- that is 96 pounds). A "One-off-fix" -- where they will come and check out the boiler and replace any parts necessary *EXCEPT* the heat exchanger (which is fearsomely expensive) -- is ?260. A one-off fix does *NOT* include a service .... but you can have that at half-price if, instead of getting the One-Off, you pay ?347 for a year's cover.

So: in for a penny, in for a pound: I paid ?347 for a year's cover, plus ?48 for an annual service to be done when the boiler was fixed. That is: ?397.

Part 3: Glow Worm visit

The chap from Group Service (GW's maintenance division I take it) arrived next day, Wednesday: he phoned about 0800 to arrange and confirm a time of arrival. Got straight down to it - had been properly briefed.

He had a good look at the system running; decided that for starters he would change the pump, if for no other reason than to get that out of the way: he said that the pump should not in any case be making the noises that it was (humming, etc.) Took off the Grundfos Super Selectric and replaced with a Grundfos "Alpha2L 25-60 130". This took him about 15 minutes. [I boggled at how long it would definitely have taken me, leaving out all the tremulous wavering about what I ought to do next, and how, and consequences of a wrong step...]

He switched on the new pump: silence -- which showed how noisy the old one had been.

Then he went to observe the boiler doing its thing. You may recall that: it was getting Fault 25 "Circulation fault", and F22 (concerning heat build-up). He concluded in the end that the heat exchanger was the problem. (Alarm! Alarm!)

They don't carry heat exchangers on the van. He made some calls, and on-line fiddling on their internal website, and finally said that his mate would come on Friday and fit a new one. Also that (for some reason

-- maybe the fact that he and I got on very well) I wouldn't need to pay for it (though I have yet to find that out for sure of course).

Part 4: Glow Worm visit 2

On Friday, the second GW engineer arrived in the afternoon. Again, fully briefed, and tooled up: got straight on with replacing the heat exchanger, having first done a couple of confirmatory tests. This is a big job.

He drained down the system only to the boiler -- i.e. he didn't drain the ground floor radiators.

Eventually completed this complex job, and he showed me the old one: it was *thoroughly* gunged up with black sludge: the pipe inlet (or outlet??) he showed me was blocked about four fifths of its diameter. THIS had been the problem.

I asked why it was gunged up, if inhibitor is in the system? To my surprise he kind of shrugged and said "just one of those things". I asked if it would be worth draining down the whole system (i.e. down to the lowest point and he replied "No -- not worth it". (This surprised me as well.)

He then did the service on the boiler, which took a lot longer than I'd expected, given that he'd just had the thing in bits. (But he was definitely working!!) He was here over two hours, and didn't stop for a minute.

Part 5: Conclusion

So instantly, we had a warm house again. The radiators, and the domestic HW, have never been so hot for months -- possibly years. The decline in the efficiency had been so gradual that we didn't notice a problem until the boiler actually conked out. (The climate doesn't help, swinging between warm and cold ambient temperatures, as it does even in winter.)

Of course I'm wondering how long it will be before we have a fault again, but I'm now committed to getting a boiler service done annually

-- probably by Glow Worm, because after all they are the manufacturers. I don't like it, because I feel they have you bent over a barrel -- but this is the world we live in.

If anyone has read this far: I hope it's been useful!

One final thing: I'm now wondering if I ought to drain the bottom half of the system (i.e. the half that the engineer did not drain), since if there is gunge in the system surely that is where it has gathered?

John

[The Natural Philosopher]

..that happen to badly made crap boilers that are made by the company that employs him ....:-)

[John Rumm]

You underestimate our boredom threshold (or level of geekiness) ;-)

You probably need a top up every few years - the oxygen scavenger in the inhibitor will get used up over time.

Was it a condensor? If so, making sure the system is scrupulously clean prior to installing the boiler is essential, for a decent boiler life.

[snip]

Yup that sounded like a fairly safe bet from your description...

Personally I would take the opportunity to isolate water path through the boiler, and do a proper flush of everything else at this stage. I would also fit a cyclonic/magnetic filter before the return to the boiler.

(mains water fed from the filling loop would be adequate usually)

Its what I would do in the circumstances. If you add a filter unit, then that's also an easy place to add inhibitor in the future.

You isolate the filter with its taps, withdraw the magnet from the sleeve, and then drain the content into a suitable container. That immediately gives you a "health check" on the system cleanliness. Close the drain tap on the filter, take the lid off, and now refill it with inhibitor rather than system water (they hold about half a litre - so either use a super concentrate inhibitor, or do it twice). Finally replace the lid, stick the magnet back into the sleeve, and then open the taps and let it circulate normally.

[newshound]

• 1 on every point (from geekiness to filter).

Slighlty surprised they did not say the same thing, but perhaps it doesn't make so much difference to you now that you have a contract.

[Fredxxx]

Yet one I was looking at, the Sentinel Eliminator System Filter installation/instruction manual doesn't mention this easy way of adding inhibitor?

Are all the manufacturer's the same?

[Bob Minchin]

You beat me to it John. I was going to suggest a magnetic filter. I fitted one a year or so ago when I changed the boiler. All rads were removed and flushed with garden hose end to end/corner to corner but still amazed at the amount of crap picked up by the filter - I must have taken it off about 4 times for a clean now and still producing some gunge. Marvelous devices.

Bob

[Bob Minchin]

Garden sprayer with modified hose to connect to a fill point. I use half of an old washing machine hose. Pump up until sprayer is virtually empty but try not to inject too much air as that will have to be bled out.

[Fredxxx]

That's certainly one way of doing it!

I was hoping that these magnetic filter systems would be an easier way of adding inhibitor, just feels strange that manufacturers don't suggest it.

[John Rumm]

I found since installation (two to three years ago) mine has probably collected about a table spoon full of magnetic solids. Still better there than in the boilers HE.

[Brian Gaff]

Actually, as an aside, a friend of mine was also told not todrain the system completly. He was told that after a short time of running the amount of sludge willdisipate and not cause any problems. as for heat exchangers, it has something to do with the heat and impurities in the water I think, Its gunge and limescale usually. However, I myself don't particularly like gas, so I don't have this sort of ch. Brian

[alan_m]

+1

I fitted one about a month ago and it has caught a substantial amount of (magnetic) crap - albeit from a system that is 15 years old - and has had regular dowses of inhibitor since installation.