Partially drained Y plan, refilled ... now not working.

[FrankE]

I have a Y-Plan system (Ideal w2000 40, Grundfos P/P, Honeywell V4073A 3019/ Randall 102 switch, LWC1 Wiring Centre, no roomstat [appropriate links in wiring centre].) It was last drained and treated with inhibitor in June and the thermocouple changed at the same time.
I partially drained the system to replace a bleed valve on a radiator which was dripping. Water was pretty clean. The header tank for the CH didn't seem to drain but I replaced the valve nonetheless with no problems, and opened the mains water inlet V/V.
I've checked all the radiators for airlocks and they are OK.

So today although the boiler fired up, it didn;t stay on very long and as a result no heating or hot water. I stuck CH and HW on constant but after an hour still no CH or HW I checked the dump valve to ensure it wasn't left open, all the radiator bleed valves and the mains inlet valve all OK.

There was water vapour going into the header tank from the expansion pipe.

There is power going to the mid pos'n V/V at the appropriate times for HW only and CH&HW. It acquieseces around a certain position and makes a sort of clicking noise, is that right?

The pipes are only hot between boiler an P/P (1.5m run) and warm between P/P and V/V (300mm run) though this might only be due conduction.

There is power going to the P/P at the appropriate times. It appeared to be running and I tweaked open the top screw to check.

I did a fulll drain and the header tank isn;t emptying. I shut the maintenance valves, removed the pump and checked the ports for blockage, OK, fired up very briefly with tails in a safebloc and the impellers are running.

Finally I opened the P/P inlet side maintenace v/v over a bucket and the header tank is still not draining.

What to check now? Blockage between header tank and boiler? Blockage between boiler and P/P?

I'm not keen to take the boiler cover off as my gas ticket isn't up to date, I've no combuston analyser and there is likely to be Chrysotile (white asbestos) in the boiler.

I'm totally skint so can't afford getting someone in and have my 83 y/o father staying.

Any ideas?

 

[kevplumb]

blockage is likley where the cold feed joins into the system pipework

or if you have one air sep

 

[FrankE]

Air sep?

 

[powell30]

Air seperator.

You could try back filling. Done by connecting a drain point to a mains supply (tap) with a hose......make sure someone is watching the feed and expansion tank in loft for overflow. This may shift the air lock or the blockage.......but get the system cleaned afterwards

 

[FrankE]

Ah, no there isn't an air separator.
There is a 15mm from header tank to RHS of boiler, a 22mm from boiler to the pump.
There is some sludge in the tank. Not sure if it' s biological growth in th tank or boiler sludge came up the expansoion overflow.

Still can;t see why there would be sludge. Sytem was flushed last year (planned maintnenace) and flushed in June (bathroom installers requested drain down) with tretorer then both times clean, and Fernox put in the system .

There are a few bends in both pipes so cant fish a snake through to try and unblock possible sludge. Not tried a conduit snake yet.

Just to check water should flow freely by gravity from the header tank through the boiler to the pump into a bucket?

There's nothing in the boiler manual or my dated experience with burners that there would be a valve between input and output of the boiler.

Safe to fire up boiler for short period see if heat will unblock?

I'm hesitant to use drain unblocker and then have to end up flushing for evermore to get rid of NaOH residues, which are probably not the best idea with such heat.

I'm not opening up the boiler due to asbestos, that and no gas cert.


Hmm could try:

siphon header tank then boiling water in the header tank
a catheter tube try and blow / pump possible sludge out.
Any safe chemicals to emulsify possible sludge?
Fit pump in reverse with clean water to I/P side.

 

[FrankE]

Thanks.
Our posts crossed, I was typing that when you replied.

Aye that was my line of thinking with putting the pump on backwards.

I cleaned and flushed the rank a few times. The stuff isn't biological it's boiler sludge when i siphoned it there was that distinct taste of irony.

Can't get the maintenance v/v off to get a hose fitting on, so WD40 soaking in now.
Bloody gas has ran out too to open the soldered joint and poke a snake down missing the bends.

Agh, so much to do today and no time to get to the wholesaler.

 

[FrankE]

Now up and running and gently toasting this morning
The flame is a bit orange so willl be getting someone in to do a service on the boiler, which is overdue anyway.

Would the manufacturer tell me for sure if there is asbestos in the boiler from the serial number. I can't remember the installation date (poss late 80s so likely) and think it's only responsible to advise the service tech. Do they normally carry H (hazardous dust) class vacuums, PPE?