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Vaillant Arotherm Plus not kicking in for DHW

Air Source Heat Pumps (ASHPs)

Last Post by Derek M 3 years ago

7 Posts

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stepht83

(@stepht83)

New Member Member

Joined: 3 years ago

Posts: 4

Topic starter 02/11/2022 8:54 pm

Hello 😊 Thank you for letting me join. I’m just a standard civilian when it comes to ASHP knowledge so please bear with and forgive me for my simplistic questions/terminology.

We have recently had a Vaillant Arotherm Plus fitted. We have ufh downstairs and rads upstairs and have managed to set our times such that it provides satisfactory heating. However, we can’t for the life of us work out how to get it to produce DHW. Even with heating completely turned off, when the system calls for DHW to be heated, we get a brief tap symbol on the VWZ AI interface module but the heat pump does not kick in. 5 minutes later the tap symbol goes off and nothing else occurs (no water is heated, the pump doesn’t run). We have an esbe valve fitted and this does it’s job and turns ready to direct the energy to the tank to heat the water.

We have fitted the pump with a trusted plumber and electrician after being let down by a ASHP company. They are feeling their way with it along with us and this is the only stumbling block. What is weird though is that on the first day it was wired in, it DID produce DHW, but then we had a power cut over night and the next day, it wouldn’t produce DHW. Not sure if this could have anything to do with it? The system was set up on wiring day with parameters dictated by a Vaillant support tech.

Any ideas welcome! Will probably end up ringing Vaillant again, but their support line is only open when we’re at work so finding a suitable time is a bit tricky. Thanks.

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4425

02/11/2022 9:16 pm

Hi,

Welcome to the forum.

I would initially suggest powering down your system, wait 5 minutes then power it back up. Then try initiating DHW.

If that does not work, check that the temperature sensor in your hot water cylinder is installed and the cable is not damaged. Also check that the cable is correctly plugged in or connected at your controller.

If that does not work then please come back to the forum with any error messages that may be present.

👍

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stepht83

(@stepht83)

New Member Member

Joined: 3 years ago

Posts: 4

Topic starter 02/11/2022 9:44 pm

Many thanks for getting back to me. I will relay your response to my husband and try a complete power down tomorrow (I’m not exactly sure how to do that). I’m confident that the temperature sensor is installed and working because we have a read out for this on our thermostats and the temperature goes up and down as expected when we use water for a shower and when we use the back up immersion to heat water. (Should of mentioned that we are using the back up immersion to get by. However, this is wired separately to the ASHP system and the ASHP system is set such that it is calling for a temperature higher than that which has been achieved by using the immersion, so as far as I can see that shouldn’t be interfering with whether or not the pump runs when DHW is requested). Thanks again, I’ll update tomorrow.

👍

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4425

02/11/2022 11:56 pm

@stepht83

Try switching off the power to your heat pump, the controller may be powered from the unit. If the controller is still powered then look for an alternative supply. There may even be a power on - off button on the unit.

I will have a look at the relevant manual and see what else I can suggest.

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4425

05/11/2022 4:35 pm

Posted by: @stepht83

Hello 😊 Thank you for letting me join. I’m just a standard civilian when it comes to ASHP knowledge so please bear with and forgive me for my simplistic questions/terminology.

We have recently had a Vaillant Arotherm Plus fitted. We have ufh downstairs and rads upstairs and have managed to set our times such that it provides satisfactory heating. However, we can’t for the life of us work out how to get it to produce DHW. Even with heating completely turned off, when the system calls for DHW to be heated, we get a brief tap symbol on the VWZ AI interface module but the heat pump does not kick in. 5 minutes later the tap symbol goes off and nothing else occurs (no water is heated, the pump doesn’t run). We have an esbe valve fitted and this does it’s job and turns ready to direct the energy to the tank to heat the water.

We have fitted the pump with a trusted plumber and electrician after being let down by a ASHP company. They are feeling their way with it along with us and this is the only stumbling block. What is weird though is that on the first day it was wired in, it DID produce DHW, but then we had a power cut over night and the next day, it wouldn’t produce DHW. Not sure if this could have anything to do with it? The system was set up on wiring day with parameters dictated by a Vaillant support tech.

Any ideas welcome! Will probably end up ringing Vaillant again, but their support line is only open when we’re at work so finding a suitable time is a bit tricky. Thanks.

Hi Stepht83,

Did you manage to resolve your DHW issue?

Feedback is always welcomed.

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stepht83

(@stepht83)

New Member Member

Joined: 3 years ago

Posts: 4

Topic starter 08/11/2022 7:47 am

@derek-m hello again, apologies for the delay in replying, Monday is a chaotic day in this household! So we tried everything you suggested and had no joy. Rang Vaillant technical who were great and went through all settings and advised purging the system and checking all filters etc. We did this, followed by a complete power down/up as you advised. We stood and watched the controls next to the pump and despaired as the whole thing shut down as soon as DHW was requested. However, we both noticed that it shut down literally as soon as the EESBE valve which is fitted moved over to the DHW feed. We wondered if maybe there was therefore a fault with that. Husband took the valve off and after consulting a YouTube video, put it back together and reinstalled it so he knew it was correct (he’s an engineer by trade so has his head screwed on with things like that). We rebooted and requested DHW and ever since, everything has worked correctly and continues to do so (please God let it carry on that way!).

So we’re not really sure what has happened prior to that, the plumber wonders if the electrician meddled with it by accident somehow. Thank you again for your help, I will be sure to come back to you again if we have further problems in the future.

Many thanks!

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4425

08/11/2022 9:18 am

@stepht83

I am pleased to hear that you have resolved your problem and thank you for the feedback.

Does the EESBE have more than one cable connected? If so, it could be that it has a limit switch fitted to indicate to the controller that it has reached the correct position. If the limit switch is not correctly adjusted or the valve does not fully open, then this could cause the problem that you experienced.

Having an Engineer in the house can be useful on the odd occasion, or so I try to convince my wife. 🙄

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