Forums

Forums
Renewable Heating
Domestic Hot Water ...
Hot water issue, ne...
 
Notifications
Clear all

[Solved] Hot water issue, never seen this before: Grant Heat Pump and Cylinder

 
Page 1 / 2
Domestic Hot Water & Cylinders
14 Posts
5 Users
7 Reactions
3,022 Views
RSS
 Marvinator80
(@marvinator80)
Honorable Member Member
Joined: 3 years ago
Posts: 201
Topic starter 21/01/2024 11:01 pm  

This is so weird. Cylinder is heating up fine. Temp says 53 right now. But when I run the cold tap it’s hot only for a short period and then cools down very quickly so I have lukewarm water at best. 

Anyone ever had this?

Baffled of Ayrshire


   
Quote
Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 4 years ago
Posts: 3363
23/01/2024 12:04 am  

Any updates on your situation?

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb

Subscribe and follow our Homeowners’ Q&A heat pump podcast


   
ReplyQuote
 Marvinator80
(@marvinator80)
Honorable Member Member
Joined: 3 years ago
Posts: 201
Topic starter 23/01/2024 8:52 am  

Posted by: @editor
↑

Any updates on your situation?

not yet. It did resolve itself for a while yesterday but is back to the same issue now. 

We have had water pressure issues in the area due to power outages affecting pumping stations but I just don’t know. Our plumber was too far away yesterday to come but hopefully will come today.

 


   
ReplyQuote
 HughF
(@hughf)
Noble Member Member
Joined: 3 years ago
Posts: 489
23/01/2024 12:14 pm  

do you have a blending valve (TMV) on your hot water supply from the cylinder?

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.


   
ReplyQuote
 iancalderbank
(@iancalderbank)
Noble Member Contributor
Joined: 3 years ago
Posts: 643
23/01/2024 12:36 pm  

Are you sure you've describe it the right way round? Your description says the cold tap runs hot then lukewarm? Did you mean the hot tap? If so then either there's not enough hot water in the cylinder or something is blending in cold when it shouldn't be, such as a TMV.

If it IS the way you described it please confirm.

My octopus signup link https://share.octopus.energy/ebony-deer-230
210m2 house, Samsung 16kw Gen6 ASHP Self installed: Single circulation loop , PWM modulating pump.
My public ASHP stats: https://heatpumpmonitor.org/system/view?id=45
11.9kWp of PV
41kWh of Battery storage (3x Powerwall 2)
2x BEVs


   
ReplyQuote
 Marvinator80
(@marvinator80)
Honorable Member Member
Joined: 3 years ago
Posts: 201
Topic starter 23/01/2024 4:39 pm  

@hughf I would expect so. It’s a Grant pre-plumbed cylinder and I do suspect the issue is with blending. 

I’m waiting for plumber to take a look now.


   
ReplyQuote
 Marvinator80
(@marvinator80)
Honorable Member Member
Joined: 3 years ago
Posts: 201
Topic starter 23/01/2024 4:41 pm  

@iancalderbank yes, that’s right Ian. I mistyped in my opening post. It is the hot tap. Runs, gets hot and then quickly becomes lukewarm when I know for a fact there is plenty of hot water in the tank. 


   
👍
1
ReplyQuote
 iancalderbank
(@iancalderbank)
Noble Member Contributor
Joined: 3 years ago
Posts: 643
23/01/2024 4:44 pm  

Posted by: @marvinator80
↑

@iancalderbank yes, that’s right Ian. I mistyped in my opening post. It is the hot tap. Runs, gets hot and then quickly becomes lukewarm when I know for a fact there is plenty of hot water in the tank. 

ok no worries . in which case I concur with yourself and hughf, blending valve is the first place I'd check. you should be able to feel the temperature of its 3 ports change over time as you run the water.

 

My octopus signup link https://share.octopus.energy/ebony-deer-230
210m2 house, Samsung 16kw Gen6 ASHP Self installed: Single circulation loop , PWM modulating pump.
My public ASHP stats: https://heatpumpmonitor.org/system/view?id=45
11.9kWp of PV
41kWh of Battery storage (3x Powerwall 2)
2x BEVs


   
👍
1
ReplyQuote
 Marvinator80
(@marvinator80)
Honorable Member Member
Joined: 3 years ago
Posts: 201
Topic starter 23/01/2024 5:01 pm  

Thanks everyone. I’m not sure what the blending valve looks like on the grant set up. I guess a plumber will know. 😬😬😬

IMG 4587
IMG 4586
IMG 4585

   
ReplyQuote
 iancalderbank
(@iancalderbank)
Noble Member Contributor
Joined: 3 years ago
Posts: 643
23/01/2024 6:06 pm  

@marvinator80 its not a grant specific component. Find the hot water output pipe coming out the cylinder and follow it.

something like this

image

My octopus signup link https://share.octopus.energy/ebony-deer-230
210m2 house, Samsung 16kw Gen6 ASHP Self installed: Single circulation loop , PWM modulating pump.
My public ASHP stats: https://heatpumpmonitor.org/system/view?id=45
11.9kWp of PV
41kWh of Battery storage (3x Powerwall 2)
2x BEVs


   
👍
1
ReplyQuote
 Marvinator80
(@marvinator80)
Honorable Member Member
Joined: 3 years ago
Posts: 201
Topic starter 23/01/2024 7:06 pm  

@iancalderbank I can’t see anything like that. This is the bit where the water seems to mix, but I’m not sure. I guess if that’s faulty it will need replaced. Trying to gently hurry up my plumber.

 

IMG 4588

   
ReplyQuote
 iancalderbank
(@iancalderbank)
Noble Member Contributor
Joined: 3 years ago
Posts: 643
23/01/2024 7:45 pm  

@marvinator80 no thats one of these 

stops your cylinder blowing up if its gets too hot or high pressure due to some control error.

one of the pipes will go via a short route to outside. "emergency dump pipe"

My octopus signup link https://share.octopus.energy/ebony-deer-230
210m2 house, Samsung 16kw Gen6 ASHP Self installed: Single circulation loop , PWM modulating pump.
My public ASHP stats: https://heatpumpmonitor.org/system/view?id=45
11.9kWp of PV
41kWh of Battery storage (3x Powerwall 2)
2x BEVs


   
👍
2
ReplyQuote
Page 1 / 2
Forum Jump:
  Previous Topic
Next Topic  
Share:

Join Us!

RHH Awards

👉 Vote for “Heat Pump of the Year”

👉 Vote for “Best Manufacturer Customer Support”

👉 Nominate “Heat Pump Installation of Year”, “Best New Tech or Innovation” or “Turkey of the Year” here!

Latest Posts