Upgrading gate valve and heating controls

Hi Westie.

Do a surf for both your current model and modern ones like the Drayton LP722 and see if they have similar wiring back-plates. If they do, they should be a direct swap for one another.

Same applies for your Honey room 'stat - does that remove off the wall leaving a wiring backplate behind? If so, there may be replacement digital ones that are also a direct swap.

But we need exact model numbers and/or photographs before we can assist further.

(Something you may also want to consider is changing your room stat for a Programmable type so that it controls both your house temp and timings - you can set it to provide whatever temp you want at whatever times and it'll do this for you. If you go this route, the new timer you'll have fitted will have it's CH channel set to 'ON' 24hrs. But that's for later...)

As for your Honey motorised valve, is it a 3-port 'diverter' type? It clearly needs replacing, although it's possible on many models to swap chust the motor part, leaving the valve section in place - so no draining down required. But, if it's the valve part wot's sticky, then a complete new unit is best - and that's within a competent DIYer's remit, but will need a system drain-down and refill (with inhibitor added).

Do you have any reason to suspect you have sludge in your system? Is the system water dirty at all? If so, then it might be worth chucking some serious chemicals in there (eg Sentinel X800) and running it for a fortnight before fully draining down your system - and refilling and drain down again.

And fit a magnetic filter on the CH return pipe.

 

Honeywell V4073A1039 is a 22mm 3 Port Mid-Position Valve, regardless of the brand, not much difference in the prices.

Should be a standard 9 pin backplate, usually only use six of them terminals ,programmer will be a straight exchange in most cases, but some need a extra link across terminals.

Drayton LP722 & Drayton + RF Digistat here, does the job, no complaints.

 

A quick surf "Landis & Gyr RWB2 direct replacement" gives the Siemens RWB29 (Landis & Staefa) amongst others. It says it's a straight swap, using the same backplate.

I think that old Honey room stat is directly wired, so doesn't have a backplate that remains on the wall that it can be unclipped from. In this case you are free to fit just about any replacement digital room stat! (But make sure they are surface-mounted (most are), and don't need a box dug in to the wall.)

If you want a replacement that is chust a digital room stat, then the Honeywell DT90E looks good. If you want to go 'programmable', then Honeywell CM907 is, I believe, highly rated.

I'd go programmable.

That leaves what to do about the new timer. In theory, if you go Prog Stat for the wall, then the CH timer part of the new dual-channel timer will be redundant - you will leave the CH side ON permanently. However, for simplicity's sake, I'd still go for a dual-channel model like the RWB29 mentioned above - 'cos it's a straight fit.

And if you don't go programmable room stat - if you stick with a 'normal' type like the DT90E - then you'll need the dual-channel timer anyway.

When you say you removed the Honey 3-port valve without draining down, how did you manage that? As far as I know, if you remove the valve body part then you do need to drain down - unless there happens to be gate valves on all three feeding pipes?

 

Salus EP200 2 channel programmer is another good one, with a RT500RF wireless stat or one of their other stats.

http://www.salus-tech.com/products/digital-programmers-and-timers/ep200/

 

That Salus looks good indeed. Well priced too. And has a backplate (check if it's a straight swap or do wires need moving).

I wouldn't personally go 'wireless', tho', not unless it was needed. Unnecessary complexity and expense.

 

If wiring already then use it, but wireless gives you the option to relocate the stat, maybe to a better location.

 

The motorhead (cue opening riff of Ace of Spades...) part of the valve might be held on by only a couple of screws, but are you sure this is the part that's faulty and not the actual valve body? Like stuck paddles. If you remove the head then you should be able to judge whether the valve part can be moved smoothly and the full distance each way. If that seems ok, then by all means chust replace the head.

Yes, you are absolutely right that of you fit a Prog Stat then you only need a single channel timer instead of the ol' RWB2 timer. However, you will then need to 'by-pass' the CH's wiring at that point so's the new Prog room stat is still getting power. Are you up to this?

I'm chust trying to keep things simple. And I wonder if a single-channel timer is that much cheaper anyway? The Siemens RWB29 or Drayton LP722 appear to be a direct swap with what you have, but if you go single channel you'll need to scratch your head a bit more (if you look at the internal diagrams of these timers, there appears to be some 2-way gubbins going on to cope with the motorised valve, etc. so you'd need to ensure your boiler is still getting the signals it needs if you change the wiring at that point).

That Prog Stat you linked to is a wireless jobbie, so another level of complexity again. The receiver part would need wiring in to your wiring centre - is there a rectangular wiring box somewhere where all the cables - from motor valve, timer, boiler, room stat, boiler - go to?

Unless you know what you are taking on (we can only help so much from this side of the screen...) then I'd keep it 'straight swap' as much as possible. So that means dual-channel timer and Prog Stat with backplate to me

 

Westie, this is exactly what this forum is for, so you are certainly not a pain

You cannot fit the COMPLETE motorised valve without draining down the system, only the motor head. If you are reluctant to drain down at the moment, then you could also swap the head for now and then do the body next Summer?

Ok, the other stuff. If SF is your only option, then the Drayton LP722 looks like your best choice, and there's now't wrong with that - it's a decent unit. http://www.screwfix.com/p/drayton-lp722-mk4-programmer/26078

When it comes to your Prog Room Stat, you have lots more options. This includes the very cheap, but seemingly well regarded, iQE7 http://www.screwfix.com/p/iqe-7-day-programmable-room-thermostat-with-li-ion-battery-back-up/53575

http://www.screwfix.com/search?search=programmable+room for alternatives.

All Prog Stats will be compatible; it largely comes down to features and ease of use. I'd be tempted by the iQE& to be honest (But make sure you are happy too...)

If you want to hold out for the Honeywell CM907, then bear in mind your old room stat seems to be working ok so you could always leave that part and order the CM907 from somewhere else and then fit it later when it arrives. (But I still fancy the iQE7...)

I think your old Honeywell room stat might be hard-wired so doesn't have a wiring backplate. This means that whichever Prog Stat you replace it with will need attaching to the wall and the wires shifted over. Don't worry - this will be easy. We'll guide you.

Something to bear in mind is that most Prog Stats are battery operated these days, so you'll only actually be transferring TWO wires over to it from your old stat, with the Neutral no longer being required (this gets safely terminated behind the new 'stat).

 

Cool.

You'll need to get in to that wiring centre box to replace your motorised valve. Note down VERY carefully where each wire goes.

You won't need access to the box for the timer/prog stat part of the job. All you should have to do for this part is swap the timer where it is (hopefully a straight swap) and the prog stat (hopefully easy...)

All of the boiler's and CH system's electrical supply should come from ONE single switch - that is a reg so there is no risk of 'cuting yourself. However, always check with a tester as it may have been DIYed at some point...

 

This is useful: http://www.draytoncontrols.co.uk/sites/default/files/LP722 (U.&I. Guide).pdf

This suggests it has the 'industry standard' backplate, so is a direct replacement for the L&G RWB2 amongst many others.

The terminals of the unit are identical: N L 1 2 3 4 (Neutral, Live, HW Off, CH Off, HW On, CH On.)

The RWB2's : http://w3.siemens.co.uk/buildingtec...l-controls/documentation/Documents/rwb2_i.pdf

Make sure the wee switch on the back of the Drayton is set to 'P' for pumped system and not 'G'.

Job's a jobbie.

 

Almost certainly it'll be 22mm. There's enough difference betwixt this and 28mm to make basic measuring fairly conclusive.

Got an adjustable spanner? Close it on the pipe until it touches, remove and measure the jaw opening. Or, get two straight blocks - even books - and place them either side of the pipe, judging by eye that they are parallel to eachother. Measure the gap.

Or, wrap a piece of string/tape/paper etc around the pipe and mark on it one exact turn. Circ should be nigh-on 70mm for a 22mm pipe or 88mm for a 28er.