I thought that the essential bit was the bleed screw to be above the impellor end but your other post gives a limit to that in horizontal pipe runs as a vertical shaft isn't allowed.
Is there a photo/scan of pump installation instructions in the wiki? It not it would be a useful addition.
You've replied to "The Wrong John"(tm).
I'm sure "Another John" will appreciate the comment though. :-)
I guess it is because the immersion heater has a different thermostat from the CH coil (and is set to a different temperature).
Also, if both CH and HW are failing together then that suggests the circulation pump rather than gunging up.
Robert
Interesting pictures, which open up another possibility! You appear to have a by-pass circuit, with an automatic by-pass valve - which is relatively unusual on a Y-Plan system. [The right-angled valve with the red knob, in front of the tank]. This is supposed to provide an alternative water path during periods of pump over-run in cases where (say) all the radiator TRVs are closed. It's only supposed to open when the pump pressure rises as a result of there being no other path.
*However*, if that valve were incorrectly adjusted or had failed open, most of the hot water from the boiler would take the line of least resistance and go round the by-pass rather than through the radiators or the internal coil in the cylinder. Under these circumstances, the radiators and HW would struggle to get hot even if the pump were ok.Might be worth running the system again and feeling which pipes get hot. If the pipe in and out of the by-pass valve are a lot hotter than the pipe going to the upper cylinder connection, that might be your answer!
Wow(!). Thanks Roger. Tell you what: I ain't half glad of this burst of summer we've been having! (and of having an immersion heater as backup to the CH HW).
I'll look at the by-pass valve tomorrow ... I knew what it was (because the heating engineer (thanks Derbyborn for correct terminology!) left me the pamphlet when it was installed. Don't understand a single word of it, but I have it ..
Thanks again everyone, for the help. Keep it coming for as long as you like! (or until I post a glowing "job done!" report).
John
Something else that might be worth looking at is the tank insulation.
The tank stat indicates about 1/2" an inch of insulation, assuming that the back of the stat is on the metal of the cylinder (as it should be) not on top of 2" of sprayed on foam insulation. I doubt that there is any foam insulation looking at the pipe connections though.
It's a big tank, one might have to play with several jackets to fully insulate it with a new layer. Also don't be afraid of putting more than one extra layer on, they aren't very thick. Two or three layers on top of what you have is not a problem and will perform better.
A well insulated tank might not go down to well with SWMBO'd if the space was also used as an airing cupboard as it would now be considerably cooler.
Page 15 of
suggests that the OP's pump is mounted correctly.
Probably the last entry to this thread, because I am giving up hope on isolating my problem, despite all the kind and detailed help...
In response to Roger's suggestion above, this morning I did the following:
- nothing came out; I then turned the impeller with screwdriver - free.
Later today I switched the water heating ON again, to see what would happen. This seemed to confuse things, although I can't be precise about how.
So I am now suspecting the 3-way valve.... but this wouldn't explain the overall problem which kicked the whole thing off, which is that the system seems to take a long time to heat up, if at all, the boiler failing with a Fault Code (indicating "Circulation Fault"), the year-old vibration noise in the whole system, etc etc etc.
Looks like I'm going to have to (a) find a heating engineer who will look at it and (b) pay him to do what I (with the vast amounts of help I've received here) have been doing ... buggering about looking for the problem. Except the heating engineer will probably simply replace one thing after another until it seems fixed, and then present me with the aggregated bill ... hence why we [try to] DIY!
Thanks for all the help, everyone! John
This says it was not operating. If in bypass mode both pipes either side of the valve would be hot. This suggests no blockage.
What are the pipe temperatures around the diverting valve?
In theory the vertical pipe should be hot, and one branch hot and the other cold.
I still suspect the pump.
If I was in your shoes I would have the HW timer set to off and the hot water cylinder cold, or at least cold for the bottom half by running off a load of hot water. I would then set HW timer to on and CH off such that the boiler fired up only for HW.
I would then check the primary pipes in and the pipe out of your hot water cylinder, monitoring temperatures. I would expect the output (lower) pipe to get fairly warm after a few minutes. If the top pipe is burning hot only after a long while of the boiler firing and the lower cold, then I would suspect the pump and remove it to check.
I would say the pump is still a likely failure candidate! The fact it runs is one thing, but I'm left wondering if the impeller is intact. I would expect to get whooshing and other circulating noises from connected pipework when the pump is running, especially on the highest speed.
Fred -- thanks a lot for your input :)
I think we agree: What I meant was: it was "functioning correctly" rather than "operating", in that it had not opened ... which it shouldn't if the system has no blockage, as you have said.
Yes - this is all as expected and as you describe.
[rest of your post deleted for brevity]Well I'm glad to hear that! A simple swop-out would be a nice solution, although I think I'd still get a professional to do it.
Thanks for your post, which has much to ponder, and encourages me. Meanwhile we are managing well: ambient temperatures are easily bearable (even here in the NE, with this sudden dip in the weather), and the immersion heater is great![1]
John
[1] We have almost never used it in the 30 years we've been in this house. However with just the two if us now, and both mean buggers, we are finding that it gives us ample hot water ... which has never been so hot, with the CH system!
The cylinder stat can be turned up if its important!
As you might gather this is a DIY group, given the cost of a heating engineer and his markup on any items he fits, it's difficult to understand why you would want to get a man in! His cost can pay for a lot of tools you get to keep.
Its the right time of the year to work on a CH systems where it can be left part finished for a week or so, and you can always get guidance and help here.
It's good to have an immersion heater as a standby but, with the relative price of electricity vs gas, it's much cheaper to use gas (when it works!).
Last week yes, but not now. Gritters out an about spreading salt this evening and it's 1.4 C air temp outside as I type.
Whilst I'm inclined to agree I'm not sure a "simple" CH pump swap is a good thing to start with. In theory you just close the valves, undo the two flanges, slide the old pump out, slide the new in with new rubber washers, tighten the flanges, open the valves, bleed pump, run system for a bit, bleed pump again. No more than an 30 mins...
But as has been detailed before in this thread it's highly unlikely to be that easy and simple.
...
Aye -- I have bitter experience in the past, especially with anything involving plumbing, of spending a week doing "a day's" job, and progressively going off to get more bits, and making a right mess of the plumbing into the bargain. With the result that these days I'm very chary of plumbing, and especially something as fundamental, and sophisticated, as a CH system.
My seeking advice here has been based on
(a) was it summat simple that I *could*, in fact, fix myself? (e.g. "drain and refill the system" (not that simple, in itself!))
(b) what is it likely to be?
(c) to **understand** how things work: I do NOT just like to have things fixed, I like to understand why they broke and how they have been fixed. The great principle in DIY is that you fix something by carefully taking it apart, finding what's wrong, and then fixing/replacing it. Then you have learned an awful lot. You cannot "take apart " a CH system to fix it in the same way that you fix a vacuum cleaner, or even a car engine [in the old days!].
So anyway - thanks Boys, again, SO much: I will report back when the job is finally done!
John
unlikely
Ah but you were finding out and learning about all the gotchas as you went along. With the pump you know from the experience of others that it might be simpler to just drain down, cut the pipe work and fit new pipe stubs, new (ball) valves, new rubber washers and new pump.
If I was faced with this problem I'd get all the bits required to complete the cut the pipework method, checking that the valves could be returned for a refund if not used. Then see if the the pump flanges will come undone. If they both move, see if the (gate) valves feel as if they have decently closed, fully open and close them, hard, several times to try and get any scale off, cautiously proceed to remove the pump with plenty of old towels about to catch any spillage. Judging how well the valves have shut by how much water continues to appear after the initial spill. Failure at any of the steps would trigger an abort to the drain down/cut pipes method but you aren't committed to doing that at that time, just tighten what has been loosened and prepare for the bigger operation.
The desire to know how and why things work and ways to fix 'em should be nurtured not smothered or rejected by the odd disappointment or "bad job".
First pump lasted 30 years, replacent because new boiler was fitted 6 years ago. Current pump is 6 years old.
My pump was installed, by me, in 1988.
In message , charles writes
Pump in my late parents house was installed in about 1965 and failed within a year, the replacement is still running! It is slightly more robust than the average domestic pump, but even so quite amazing.
Damn, that's jinxed it............
In message , Bill writes
I don't know, but AFAICT the CH system here was probably installed in the 1970's, though maybe the late '60's. It looks like it still has the original pump - a large and sturdy Grundfos
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