Help me bodge some temporary repairs to this monstrosity

[joth]

Backstory: I'm renting a friend [and fellow self Builder!]'s house while ours is renovated. Due to COVID delay now looks like we'll be here through to the next heating season so thought it worth getting a gas service, and see if I can get the DHW working again. There's been a long standing issue that the DHW zone valve gets stuck due to an airlock (presumably because of some unknown slow leak somewhere) so we've been using immersion heater for 2 months. The gas man wanted £300 to drain the system so I said stuff that I'll do it myself.  The whole house is in line for demolition, so not worth spending much on, this is all Acme Bodgit & Scarper land.

However, in my eagerness to investigate I touched a bypass/isolation valve of unknown purpose, that started to leak (video) and dripped all night, so I've now drained the system and am enthused to learn how to solve this, as it is good prep for when our own install happens later this summer.

 

 

Here's the mess (closer up).

 

And here's my attempt to label what's going on:

 

 

 

Plan of attack/ question:

 

1/ Remove the leaking bypass valve and cap off the pipes. I believe this valve is closed (?) and I don't know what it's for (it seems to connect flow directly to return, bypassing both zones?). For a minimal working system, I don't think we need it.

Q: what's best way to cap it off?  It's connecting 15mm pipe either side.

 

2/ Replace the stuck DHW zone valve with straight pipe. What's the best way to do this? It's 22mm on the right feeding into 28mm on the left side.

(I *think* I've just about forced the valve into the open position, but hard to be sure it will stay there?)

Obviously this will mean we can't run heating without DHW also running, but that's a fair trade off for "just a few months" usage.

 

3/ Electrically disconnect the (now burnt out) DHW valve head. This seems to have a microswitch in it that needs to be press if (and only if) the timer is allowing for DHW to be on. I think this is S-plan wiring, so I think I can just use the "motor open" signal to trigger the call for heat directly. i.e. connect the Brown wire to the orange wire, if it is following this diagram?

 

In summary:

 

 

 

4/ Bonus question: how to test all my replacement connections, other than fill it all up and wait?

 

Cheeers!

 

 

[ProDave]

Why do you want to do anything other than fix it?  Why change things?

 

The "bypass valve" is an ordinary service isolator.  Easy to just get a new one and replace it.  BUT is should be an automatic bypass valve.  That only opens when you get a certain water pressure, typically when the pump starts but in the time before the motorised valves actually open.

 

Likewise that's a Honeywell 2 port valve.  An air lock would not physically stick the valve, it is broken.  So replace it with another.  If you want to do cheap, the cheaper Tower ones are pretty much a copy of the Honeywell.

 

And since you will just be changing two things like for like, there is really no plumbing to alter.  However you will be re using the olives on the pipes, so give each a few wraps of ptfe tape to increase the chance of them re sealing.

 

Just replacing the broken bits will make the system operate as it should and save you having to bodge the wiring to frig it.

 

Do take care to do a drawing or photograph the wiring of the old zone valve before you remove it and make sure the new one connects exactly the same.

 

Possibly the hardest part of this will be finding enough slack in the pipe work to pull the pipes apart a little to get the old valves out and the new ones in.

[joth]

1 minute ago, ProDave said:

Why do you want to do anything other than fix it?  Why change things?

I'm being a cheapskate - it's someone else's home and they're going to demolish it and the end of the year so just wanting the minimum needed to make DHW work again.

There definitely is cost/effort trade off I'll grant you.

[PeterW]

That is an 82p isolator valve - just undo the nuts and replace with a lever valve of the same size. The nuts and olives can stay in place, good squidge of LS-X for ultimate bodginess and you will be fine. 

I would leave the zone valve in place and wedge it partially open - no point in changing it unless you need to, otherwise it would be a 22mm lever valve for me and a 28/22mm compression reducer and a short length of 22mm copper pipe. 

 

[ProDave]

If you can persuade the zone valve to actually turn, with a spanner on the flat of the actuator and once turning give it plenty of exercise until free, then just change the actuator head if it really is burned out.  What makes you think it is burned out?  You can't always test the Honeywell heads off the valve base as they have a habit of the gears disengaging and them going twang, which may make you think it is faulty when it is not.

 

So get that valve body turning and try the actuator head on.

 

If the only issue with the "bypass" valve is it is leaking, put a bucket under it.

[joth]

56 minutes ago, PeterW said:

That is an 82p isolator valve - just undo the nuts and replace with a lever valve of the same size. The nuts and olives can stay in place, good squidge of LS-X for ultimate bodginess and you will be fine. 

 

OK. I think it was my inherent hatred of these screwdriver driven isolators reinforced by the thing squirting hot black water the moment that touched it, plus suspicion I didn't even know why it's there (when would you open it up?) that made me just want ride of it. So I was wondering if these more reliable for my level of plumbing skill, but sounds like a direct replace is the way to go. Great tip on the LS-X too... that sounds like magic paste.

 

1 hour ago, PeterW said:

I would leave the zone valve in place and wedge it partially open - no point in changing it unless you need to

 

OK - it's really stiff to move the valve tap. The gas check plumber  was reluctant to to force it and said it needs replacing to get it open, I pushed a bit more and think I got hot water to pass through it (before I made the other leak and had to drain the system.....). but I fear it is only part open and liable to close again, if they can do such a thing?

 

 

 

 

56 minutes ago, ProDave said:

What makes you think it is burned out?

When I took it off, it made some horrid grinding noises, got really hot, then when I poked it it went, sort of like, "twang" 

 

58 minutes ago, ProDave said:

You can't always test the Honeywell heads off the valve base as they have a habit of the gears disengaging and them going twang, which may make you think it is faulty when it is not.

 

 

Ah, thanks! That's exactly what I did then.

I did poke it a bit more to try and re-engage ... but now have a collection of loose springs, a corroded ratchet gear things, and a motor that gets hot and angry (but surprisingly silent) if powered up. 

 

The thing I probably didn't make clear is this is the third time this valve has stuck  in about 6 months. The previous tenants had a plumber in to unstick it a couple times, and then when it got stuck again in March for us I just said stuff it let's use immersion heater (having DIY repaired that, which I'm quite proud of all told)   :-)

 

The root cause is suspected to be an existing leak that is drawing the air into the system and hence blocking that valve. Two plumbers haven't found it and just said they'd need to replumb the whole damn house to be sure they'd fixed it!

So if I can jam the valve open, I'm reluctant to replace the motor as all it will do is close the valve and then that will inevitably get stuck again... if I can jam the valve permanently open then we can then use the system for DHW.

 

Thanks!

 

[ProDave]

Air will not make the valve stick.

 

The dirty black water suggests there is no inhibitor and everything is rusty as hell and corroded as hell.

 

 

[joth]

Just now, ProDave said:

Air will not make the valve stick.

 

 

I was curious about this. On 3 callouts (2 companies) that's the only explanation given (weell, alongside "the whole system design is a mess"; I think the boiler was moved at some point and resulted in a web of piping)

I'm not in a place to defend it either way.

 ¯\_(ツ)_/¯  

 

1 minute ago, ProDave said:

The dirty black water suggests there is no inhibitor and everything is rusty as hell and corroded as hell.

 

Probably. While the loft is littered with discarded inhibitor bottles, it's bound to have been skipped on some occasion. (But isn't radiator water always black...?)

 

Other factors:

- we have very hard water, 312 mg/l ...

- I think the house was left empty for a while (probate?) so that tends to be when the seizing up sets it.

 

 

 

[joth]

Small update:

 

Well, I bought a new isolator valve today from the shop at the end of the road. Couldn't bring myself to pay Toolstation £5 postage so instead paid £6 for it locally!!

 

Managed to get the compression nuts undone off the old one but not enough slack in the pipework to allow me to pop it off the pipes. Olives solidly jammed in place, so no idea how to get it out to put the new one in?

 

Anyway for kicks I tried the rest of the plan: forced the stuck zone valve open as best I can and rewired the wiring box to bypass the zone motor, connecting cylinder stat return directly to the call for heat (brown to orange). Refilled system and bingo we have working hot water again, and a slow dripping bypass valve. Current plan is to let it drip in a bucket for a couple days and hopefully the calcium will seal it back up ? 

Otherwise, er, I'll have to go at it with something more brutal. Presumably hack one olives off to get enough wiggle room to remove the valve, and hope I can get it reassembled. Really wish I knew what purpose it serves though??

 

Edited May 28, 2020 by joth

[PeterW]

Ok so see the big nut just above the knackered zone valve ..?? 
 

Undo that, and remove that you will allow the rest of the pipework to move - the isolator should release then. 

[dpmiller]

or pipeslice the one directly beneath the isolator and stick a straight coupler on.

[joth]

9 hours ago, PeterW said:

Ok so see the big nut just above the knackered zone valve ..?? 
 

Undo that, and remove that you will allow the rest of the pipework to move - the isolator should release then. 

 

Thanks @PeterW ! 

I did glance briefly at that big coupler but figured the isolator only started leaking after I tried fiddling with something I didn't understand and I didn't want to make yet more problems for myself trying to fix this one ?

I've wriggled the isolator screwhead repeatedly and somehow got the dripping to virtually stop, hopefully that holds but if not this definitely looks the simplest way to remove it all, at least for someone like me with a irrational fear of cutting and joining water pipes. (so weird, I find electrics trivial in comparison)

 

[joth]

On 27/05/2020 at 14:45, ProDave said:

The "bypass valve" is an ordinary service isolator.  Easy to just get a new one and replace it.  BUT is should be an automatic bypass valve.  That only opens when you get a certain water pressure, typically when the pump starts but in the time before the motorised valves actually open.

 

Rereading this now having messed about with it more, I think the leaking one could actually be an automatic pressure relief bypass? At least, it has a directionality arrow stamped on it, which only makes sense if it is, right? And it'd make far more sense than just a straight isolator there. 

 

Anyway as I've wedged the zone value open this should "never" need to open now (famous last words?) 

 

 

On 27/05/2020 at 14:45, ProDave said:

Possibly the hardest part of this will be finding enough slack in the pipe work to pull the pipes apart a little to get the old valves out and the new ones in.

Yup you were exactly right on that too !

Edited May 29, 2020 by joth

[dpmiller]

nope, normall isolators have an arrow on as the seal is only perfect in one direction.

[joth]

51 minutes ago, dpmiller said:

nope, normall isolators have an arrow on as the seal is only perfect in one direction.

Good to know! The replacement I doesn't have an arrow which is what was misleading me.