Hot water cylinder smart thermostat

[Michael Groves]

I’m looking for a Hot Water Cylinder Smart Thermostat. But I want to be able to monitor the tank temperature over time so I can see when the hot water is being drawn off and how quickly it recovers. So maybe recording the temperature every 5 minutes and saving this data.

Does such a thing exist?

 

[chris watkins]

I haven't seen one, sounds more like a data logger more than a thermostat.
Can one ask why you want such a beast Michael ?

 

[Riley]

Yes I agree

 

[chris watkins]

WiFi Logger ThermaData TD1F - two channel thermistor logger with internal sensor & remote probe
Maybe something like this would work ?

 

[Michael Groves]

WiFi Logger ThermaData TD1F - two channel thermistor logger with internal sensor & remote probe
Maybe something like this would work ?

Perfect, I had not even considered this. I was fixed on a smart thermostat.

I have a 300L unvented cylinder, this serves 6 tenants, 2 showers. It has a secondary return and tank heated 24/7 by 20kw boiler. Until recently it’s never run out. But in the last 2 weeks we’ve run out of water twice.
Before even considering upgrading I want to understand what’s going on.

 

[SimonG]

When was it last serviced?

 

[Michael Groves]

When was it last serviced?

It’s a new install, installed December 2017. What would need to be serviced?

Bit more info, it has a 19kw heat exchanger, reheat time 45 minutes.

 

[chris watkins]

Safety valves discharging ?
Heating on at the same time as the HW?
Don't ever be tempted to replace/remove/disconnect the unvented thermostats & fit another type of stat, as that would not be a very "SMART" thing to do!!!!
I have seen it done with the rush for so called smart controls & it could be very dangerous. Get a G3 plumbing in to take a look might save yourself £100.

 

[SimonG]

It’s a new install, installed December 2017. What would need to be serviced?

Bit more info, it has a 19kw heat exchanger, reheat time 45 minutes.

Boiler and cylinder, annually.

 

[chris watkins]

It’s a new install, installed December 2017. What would need to be serviced?

It is an unvented cylinder servicing a tenanted property of course it needs servicing, did you not read the manufacturers instructions ?

 

[SimonG]

Any pics of the install?

 

[Michael Groves]

It is an unvented cylinder servicing a tenanted property of course it needs servicing, did you not read the manufacturers instructions ?

I deserved that, it was a bit of a dump response. Boiler serviced yearly, I was referring to cylinder but did not make it clear.

I did not get cylinder serviced, I’ll ask plumber about that tomorrow.

Glad you commented about not changing thermostat. I’ll also mention this.

I’ll see if I can find a picture tomorrow.

I still like the external data logger idea.

 

[Chalked]

I had one last week.
Complaining of lack of hot water and not hot enough.
It was the prv passing, so was like a tap running all the time.

 

[chris watkins]

Ask to see there G3 ticket please, to work on them they must have one.
What area of Kent are you Michael ?

 

[Michael Groves]

He’s defo G3, either going on refresher course shortly or just been on it. Albeit how can you check, is there a register like Gas safe?
It’s in Hastings.

 

[Riley]

Likely it’ll be on their gas safe card

 

[Michael Groves]

My G3 plumber is not gas safe.

 

[chris watkins]

Hastings too far for us , unfortunately no register, there perhaps should be.
Problem is always those that install don't always know how to repair or even sometimes service them. I take it, it was notified to local BC.
Ask for a copy of their G3 / unvented Certificate, they shouldn't mind & at least you will be covered if there are any problems.

 

[Michael Groves]

I know the boiler was registered with BC, not sure about cylinder, is that a requirement?
Shame about the register, that does sound like an oversight by our government.
How often do you need to refresh your G3 to stay compliant?

 

[Riley]

Every 5 years. And they will have an ID card and cert

 

[Michael Groves]

I asked my plumber about servicing cylinder, he was hell yeah, you need to check this n that and that n this. Made sense having spoken to him. He said look at back of booklet got with cylinder, need to dig this out.
I also took a photo

 

[Riley]

Looks to need some D1 discharge reposing as it’s not to spec

 

[Michael Groves]

What does that mean, I asume 3 no. 15mm into 1 no. 22mm does not comply, am I correct, if so why not?

 

[Riley]

500mm max before it passes through tundish

 

[Michael Groves]

500mm max before it passes through tundish

Tundish is behind immersion heater, zoom in, you can just see bottom below immersion. I’ll measure runs. But otherwise is it okay?

 

[Riley]

Difficult to say without being there. Certainly D1, no insulation. Might be more

 

[Harvest Fields]

G3 advice on an open thread? You need your G3 engineer on site to look at this properly mate.

 

[Michael Groves]

No worries, I’ll ask him to review.
Thanks for heads up.

 

[ShaunCorbs]

Them esi stats are a pain check your cylinder temp is correct eg hot water temp 60 - 65 Dc stored

 

[chris watkins]

500mm max before it passes through tundish

600mm now & has been since they went with the re-assessment.
Michael check out MI's or otherwise Building Reg's AD PartG3 page 24
https://assets.publishing.service.g...207/BR_PDF_AD_G_2015_with_2016_amendments.pdf

 

[chris watkins]

No worries, I’ll ask him to review.
Thanks for heads up.

More importantly Michael from what I can make out from your photo you have a Grundfos AutoAdapt Comfort 15-14BA PM secondary hot water circulator installed, & from what I can see, the sensor has been fitted to the return pipe not the flow out of the cylinder so the pump can't learn your usage pattens & maybe running all the time. Along with the fact that there is no insulation fitted to the pipework this will be wasting lots of energy (gas) & I believe that was why you originally posted.
Please check it out & let us know.

PS. it is a requirement under the Building Regs that the hot (flow & return) pipes are insulated.

 

[Riley]

I tell you what Chris thanks. I even knew that but doubted myself and the first pic of dimensions I googled was wrong

 

[Riley]

Damn google

 

[Michael Groves]

600mm now & has been since they went with the re-assessment.
Michael check out MI's or otherwise Building Reg's AD PartG3 page 24
https://assets.publishing.service.g...207/BR_PDF_AD_G_2015_with_2016_amendments.pdf

Thanks for link, I’ll get tape measure out on Friday when I am there, I think it’s okay, but I will confirm. I’ll also dig out MI while I’m there.

 

[Harvest Fields]

Thanks for link, I’ll get tape measure out on Friday when I am there, I think it’s okay, but I will confirm. I’ll also dig out MI while I’m there.

Is this a rented property?

 

[Michael Groves]

More importantly Michael from what I can make out from your photo you have a Grundfos AutoAdapt Comfort 15-14BA PM secondary hot water circulator installed, & from what I can see, the sensor has been fitted to the return pipe not the flow out of the cylinder so the pump can't learn your usage pattens & maybe running all the time. Along with the fact that there is no insulation fitted to the pipework this will be wasting lots of energy (gas) & I believe that was why you originally posted.
Please check it out & let us know.

PS. it is a requirement under the Building Regs that the hot (flow & return) pipes are insulated.

You have a keen eye sir, unfortunately I can’t blame plumber for Grundfos sensor. Original Grundfos did not have sensor. It only lasted 6 months and failed. It was replaced under warranty, but they no longer made the basic model so sent one with sensor. I swapped it as it was straight forward. It’s still runs 24/7, when I did the maths, the extra money for the more expensive pump had a pay back of 10 years. That’s why I went for cheaper one initially. However, when I got top pump for no extra money I reviewed again. I spoke with Grundfos in case I was missing anything, but we came to same conclusion. Because usage is sporadic autoadapt won’t work. So it’s left running 24/7. The sensor is just clipped out the way.

All pipe runs have been insulated with the fattest pipe insulation I could get. The only pipe not insulated are what you can see. It’s been left off so I can paint first. But, I wish plumber had used spacers so I could get thicker insulation on.

On that note, I’ve been meaning to post this question for ages, there is a noticeable temperature drop the further you get away from the cylinder. Assuming we are only talking about secondary return, there is only 2M of uninsulated pipe on the whole run. I fully expect a drop, but it just seems too much. Everything is Hep2o other than what you see.
What else can I do?

 

[Riley]

Secondary I don’t believe can be plastic

 

[chris watkins]

The flow should be 60 - 65 & the return at the cylinder no less than 50. However good the insulation you will still have standing losses of the cylinder & the pipework.
You may wish to speak to the manufacturers of the pipe as I believe the warrantee will be void if you use it in a secondary circulation circuit especially one that runs continually.
PS. you should of specifier clip spacers to suit the lagging 😳
Good luck Michael

 

[Michael Groves]

The flow should be 60 - 65 & the return at the cylinder no less than 50. However good the insulation you will still have standing losses of the cylinder & the pipework.
You may wish to speak to the manufacturers of the pipe as I believe the warrantee will be void if you use it in a secondary circulation circuit especially one that runs continually.
PS. you should of specifier clip spacers to suit the lagging 😳
Good luck Michael

I’ll check temp when I’m next there. Just to be clear, are you saying customer should have asked for spacers?

 

[chris watkins]

Yes, most standard plastic pipe clips will just about allow 13mm wall thickness insulation to be fitted around the pipe if you wanted the insulation to be thicker then you needed to spec it or let then know that was your intension.

 

[Michael Groves]

Secondary I don’t believe can be plastic

There was a lot of debate about plastic, I recall the Hep2o spec advises it has not been tested on secondary. However, Hep2o technical advised it had been tested above the pressure required for secondary return so it should be okay, but as it just has not been tested they can’t warrant it will be okay. Ultimately it’s up to you. I was given the scenario, and told it was up to me as customer to make final decision. I agreed to go with Hep2o as I believed the performance and spec supported this. The only caveat was it’s just not been tested.

 

[Michael Groves]

Yes, most standard plastic pipe clips will just about allow 13mm wall thickness insulation to be fitted around the pipe if you wanted the insulation to be thicker then you needed to spec it or let then know that was your intension.

Fair enough, to be honest I’d not considered lagging until the install was finished. Then the day we tested I was amazed at the temperature drop so got it lagged to death.

 

[ShaunCorbs]

not rated for secondary returns

Push-Fit Hep2O: Your plumbing FAQs answered - Part 1

Can I use Hep2O in a continuously operated re-circulating system?
No. Continuously operated re-circulating systems (Secondary Hot Water Circulation/Ring main installations) are very different from conventional hot water supply and central heating systems found in domestic properties, for which Hep2O products have been tested.

 

[chris watkins]

The problem is not with the pressure or even the temperature it is the fact that it is oxygenated water which if circulated all the time has been shown to break down the plastic over time.

 

[chris watkins]

"Continuously operated re-circulating systems are very different from conventional hot water supply and central heating systems found in domestic properties, for which our products have been tested to, under either BS 7291 2010 Class S or WRAS approval standards, and for this reason Hep2O products must NOT be used on any continuously operated re-circulating systems as they are not approved under the current version of these standards."

Page 59 Installation Guide.
You would have thought that the technical department would have followed their own published advice wouldn't you?

 

[Michael Groves]

Hep Technical pointed out it had not been tested, so they could not guarantee it would work. But also pointed out as it had not been tested they could not say that it would not work. If the customer chooses to use it, it is at their own risk.
What would be good if they could actually test it and say either way for sure.

 

[Michael Groves]

The problem is not with the pressure or even the temperature it is the fact that it is oxygenated water which if circulated all the time has been shown to break down the plastic over time.

But doesn't barrier pipe solve that problem ?

 

[Michael Groves]

Is this a rented property?

Yes

 

[ShaunCorbs]

They have tested it and it split

Any leaks on your hot water sys?

 

[Michael Groves]

I was told it had not been tested!

I'm not aware of any leaks, we have newly painted lath & Plaster ceilings so I'm sure if there were we'd know about it.

Its been running for about 17 months, I might send Hep my test results 🙂