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Watch Where Your Installer Fits Motorised Valves

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Mars
 Mars
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I’ve just had a frustrating experience with a Honeywell valve failure, and it’s left me wishing I’d been more involved in checking the placement of all components during installation. I empathise and apologise to my next heat pump installers in advance because we’ll be hellish clients! 😂

The valve was fitted behind the hot water cylinder, with less than 15cm of space between the wall and the cylinder. To say it’s a tight fit would be an understatement - it’s nearly impossible to access.

To make things worse, there’s no isolation valve to shut it off, meaning we’ll likely have to drain the entire system just to replace it. All in all, this setup could have been avoided with a bit more thought during the installation process. Just more shoddy installation work. 🤠

So, here’s my advice:

1. Check Placement of Valves During Installation

Don’t assume your installer will automatically think about future accessibility. Speak up and make sure components like zone valves or motorised valves are fitted in locations where they can be easily accessed for servicing or replacement.

2. Ask About Isolation Valves

Make sure isolation valves are fitted wherever practical. They’re a small addition that can save you a lot of hassle down the line when maintenance is required.

3. Inspect Before Signing Off

Before the installation is completed, do a walkthrough with your installer to confirm everything is in an accessible location. It’s far easier to fix these issues during the initial setup than to live with the consequences.

It’s small details like these that can make a huge difference in the long term. Learn from my oversight, and save yourself the stress if something goes wrong in the future!

Have you encountered similar issues? Please share.

IMG 3873
This topic was modified 5 days ago by Mars

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(@allyfish)
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Hi @editor, has the valve failed or the motorised actuator?


   
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Mars
 Mars
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@allyfish the valve is working, and when called upon, opens and/or closes. Apparently there's a microswitch inside these valves, and that's what's not promoting the boiler to come as a redundancy in our system. It usually takes care of defrosts and some heating when we drop below 0C.

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(@allyfish)
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Posted by: @editor

and that's what's not promoting the boiler to come as a redundancy in our system

Thanks @Mars. A 'boiler' you say, this is blasphemy! 


   
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Mars
 Mars
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@allyfish 🤣

Unfortunately, it’s the nature of the system we have to work with. The index circuit consistently struggles to reach target temperatures when the outdoor temperature drops to 0°C or below.

In this setup, the boiler only runs intermittently – primarily to assist with defrost cycles or provide a temperature boost when needed. While it’s far from ideal, it’s how the system is configured to operate. One of the reasons why RHH was born. An expensive system to install that has been butchered. 

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(@allyfish)
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@editor I see. I knew there would be sound reasons. My ASHP is barely big enough, and I've seen aveage room temperatures drop a couple of degrees overnight with the ASHP running when outdoor air temperatures drop below freezing. Basically, below a certain ambient temperature without supplementary heating, my ASHP seems to track ambient outdoor temperature. There are several factors causing this I think:

1. Undersized unit delivering maximum heat output. When it's defrosting however, it's not delivering 10kWh, more like 8kWh due to intermittency of operation and heat lost for defrost cycle.

2. Return temperature of radiators typically about 5degC lower than supply, which at primary flow rate of 22l/min means the ASHP is, more or less, maxed out: 5x(22/60)x4.2= 7.7kW. It can't reach target WC temperature because it can only raise the circulating water by around 5.5degK.

So it could really use some supplementary heat input 3-4kW. I can energise the 3kW immersion in the LLH, which raises the LWT by a couple of degrees, but that's a very expensive option, even with load shifting most imported electricity off-peak to low tariff. I have the setting for this set to -5degC, by which time I know the house won't be warm enough to be comfortable and will never warm up with around 8kWh of heat input. I  could raise this to 0degC, but then I'm guzzling around 6kWh of energy with ASHP & supplementary 3kW direct electric heating together. So I light the stove and burn some wood, which can quickly boost downstairs, and it filters upstairs. 

This post was modified 3 days ago by AllyFish

   
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 MPHB
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I have a bit of the same issue:

81F52199 DF9A 440E 8C39 01E818496868

However, this is DIY so I can only kick myself. The TWV is crewed on press fittings on three sides with no possibility to losen just one. So if there ever will be an issue, it will be a pretty big operation to get it all sorted. 

@editor - what surprised me most about your picture, is that your piping is completely uninsulated. Although the forum community did actually nominate you for the Nobel Prize for sustainability, this ruined your chances forever 😆. 

This post was modified 3 days ago by MPHB
This post was modified 2 days ago by Mars

   
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Transparent
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For reference, here's the classic motorised valve wiring diagram:

ValveMotorised

If the valve body itself is still operating, then you just need to exchange the head.

The white wire is only provided on valves which have ports to accept 28mm diameter pipe (or larger).
The common 22mm valves (Honeywell V4043 etc) have a 'single throw' switch.

In the case posted here by @editor it's possible that the Auxiliary Switch has stopped working because debris has fallen in through the slot from which the manual lever protrudes.
He might be able to recover the valve's operation by cleaning it out with a vacuum nozzle.

It's odd that Mars' valve malfunctioned on a Thursday evening.
They normally wait until Friday, when the stores have just closed.

Keep a spare on the shelf!!

This post was modified 2 days ago 5 times by Transparent

Save energy... recycle electrons!


   
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Mars
 Mars
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Posted by: @transparent

He might be able to recover the valve's operation by cleaning it out with a vacuum nozzle.

The 2000W Karcher will be out shortly!

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