We’d like to remind Forumites to please avoid political debate on the Forum.

This is to keep it a safe and useful space for MoneySaving discussions. Threads that are – or become – political in nature may be removed in line with the Forum’s rules. Thank you for your understanding.

📨 Have you signed up to the Forum's new Email Digest yet? Get a selection of trending threads sent straight to your inbox daily, weekly or monthly!

Problem with Greenstar condensing boiler

Atomichamster
Atomichamster Posts: 11
First Post Photogenic
Forumite
edited 20 October 2025 at 1:12PM in Energy
For a few weeks the heating has been on when the controls are set to hot water only.  Now today everything has stopped working, no heating or hot water.  Could this be the motorized valve that has gone?  I just need an idea of what it is before I call out a heating engineer.  Thanks in advance.

Comments

  • MattMattMattUK
    MattMattMattUK Posts: 13,175
    10,000 Posts Sixth Anniversary Name Dropper
    Forumite
    Atomichamster said:
    For a few weeks the heating has been on when the controls are set to hot water only.  Now today everything has stopped working, no heating or hot water.  Could this be the motorized valve that has gone?  I just need an idea of what it is before I call out a heating engineer.  Thanks in advance.
    It could be lots of things, from the information you have given it could be absolutely anything. 

    Why do you need an idea of what it is before you call out an engineer? Their job is to diagnose and fix problems. 
  • QrizB
    QrizB Posts: 25,153
    10,000 Posts Fifth Anniversary Photogenic Name Dropper
    Forumite
    More info required, please.
    Is your boiler a combi or a regular/system one? Do you have a hot water tank?
    N. Hampshire, he/him. Octopus Intelligent Go elec / Fuse gas / Vodafone BB / iD mobile. Kirk Hill Co-op member.
    2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 37 MWh generated, long-term average 2.6 Os.
    Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs, Ecoflow Stream, Best kettle :-)
  • Atomichamster
    Atomichamster Posts: 11
    First Post Photogenic
    Forumite
    QrizB said:
    More info required, please.
    Is your boiler a combi or a regular/system one? Do you have a hot water tank?
    Yes, it's a condensing boiler as in the heading and there is a hot water cylinder. 
  • Atomichamster
    Atomichamster Posts: 11
    First Post Photogenic
    Forumite
    MattMattMattUK said:
    Atomichamster said:
    For a few weeks the heating has been on when the controls are set to hot water only.  Now today everything has stopped working, no heating or hot water.  Could this be the motorized valve that has gone?  I just need an idea of what it is before I call out a heating engineer.  Thanks in advance.
    It could be lots of things, from the information you have given it could be absolutely anything. 

    Why do you need an idea of what it is before you call out an engineer? Their job is to diagnose and fix problems. 
    I just don't want to be ripped off.  I have been in the past.
  • QrizB
    QrizB Posts: 25,153
    10,000 Posts Fifth Anniversary Photogenic Name Dropper
    Forumite
    Atomichamster said:
    QrizB said:
    More info required, please.
    Is your boiler a combi or a regular/system one? Do you have a hot water tank?
    Yes, it's a condensing boiler as in the heading
    "Condensing" describes every gas boiler installed in the past 20 years. It's not really a way of identifying your system.
    Atomichamster said:
    ... and there is a hot water cylinder. 
    OK, so not a combi then.
    S-plan (with two or more two-way valves) or Y-plan (with a three-way valve)?
    N. Hampshire, he/him. Octopus Intelligent Go elec / Fuse gas / Vodafone BB / iD mobile. Kirk Hill Co-op member.
    2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 37 MWh generated, long-term average 2.6 Os.
    Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs, Ecoflow Stream, Best kettle :-)
  • 20122013
    20122013 Posts: 815
    500 Posts Second Anniversary Name Dropper
    Forumite
    Atomichamster said:
    QrizB said:
    More info required, please.
    Is your boiler a combi or a regular/system one? Do you have a hot water tank?
    Yes, it's a condensing boiler as in the heading and there is a hot water cylinder. 

    I can understand that, I have warranty with Greenstar, and I wonder whether they still have a support line? as they uses to talk you through what to check.
  • Lorian
    Lorian Posts: 6,916
    Twentieth Anniversary 1,000 Posts Name Dropper Photogenic
    Forumite
    It could well be the two way valve stuck based on your first post assuming you have a Y plan system. There will be videos on YouTube on how to test it.
  • RavingMad
    RavingMad Posts: 926
    Part of the Furniture 500 Posts Name Dropper Combo Breaker
    Forumite
    edited 21 October 2025 at 4:36AM
    Does the boiler try to fire up when you call for either heat or water?
    My old boiler (not a WB) which I never had serviced was full of gunk in the trap? Called out an engineer who cleaned it, serviced it and it was fine after that. Replaced it the following year for a different reason 
★ ★ ★ Meet your Ambassadors

🚀 Getting Started

Hi new member!

Our Getting Started Guide will help you get the most out of the Forum

Categories

  • All Categories
  • 355.8K Banking & Borrowing
  • 254.9K Reduce Debt & Boost Income
  • 456.2K Spending & Discounts
  • 248.3K Work, Benefits & Business
  • 605.9K Mortgages, Homes & Bills
  • 179K Life & Family
  • 263.8K Travel & Transport
  • 1.5M Hobbies & Leisure
  • 16.2K Discuss & Feedback
  • 37.7K Read-Only Boards

Is this how you want to be seen?

We see you are using a default avatar. It takes only a few seconds to pick a picture.
Update Your Picture