- Joined
- 15 Jun 2014
- Messages
- 99
- Reaction score
- 1
- Country
Hi all,
Have my plumber coming out this week to have a look but wanted to run the following by you guys:
Flexicom 18sx - installed 11 years old. Annual service up to 2 years ago. Problems with pressure drops since the install - we only ever have hot water on (1 hour in morning every day and booster when needed), only put the hear on downstairs during winter whenever needed. Only recently started using upstairs (children getting cold). It's not on that much really.
The normal is - we might need to top up at end of autumn (i.e. after hot water on only during spring, summer). But always need to top up every 4-6 weeks during winter (hot water and heat downstairs) - sometimes longer, sometimes shorter. As I reflect back - I think we need to top up more the colder it is. No one has ever gotten to the bottom of it after each service.
Particularly cold here over the last week and since then the pressure drops to zero after every time we turn the central heating on (which is new - which is why the plumber is coming out). In other words - top up, heat on, heat off, pressure drops <30 minutes.
Friday Night:
- Cold System; topped up to 1bar; no heat/no water on
Saturday AM:
- Hot Water @06:00 - 07:00; pressure stayed at 1 bar.
- No Heat/No Water on all day; Checked pressure at 17:00 (raised to 2 bar - not uncommon)
- CH (Downstairs) on at 17:00 - 18:30; pressure raised to 2.5 bar
- Added CH (Upstairs and Hot Water) from 17:30 to 18:30: pressure stayed at 2.5 bar
- 19:00 pressure dropped to zero; topped back up to 1 bar
- No heat/water on for remainder of night
Sunday AM:
- Hot Water @06:00 - 07:00; pressure stayed at 1 bar.
- CH (Upstairs) 13:00 - 14:00; pressure to 2 bar
- 14:30l pressure to 0 bar. (usually the pressure doesn't drop when the upstairs is used - this is certainly new).
Clearly I have a problem
- Leaks: There's none upstairs, there's none in the hot water system, there may be one in the sub-floor. All radiators have been checked and joints cinched up. I don't think there is a leak - as the issue is not consistent. It fluctuates depending on what is turned on (HW v CH) and even then only the downstairs CH and even then when its colder out (we of course is likely related to frequency of use).
- Automatic Air Vent: Not sure if I have one on the system. There's one on the hot water tank.
- Expansion Vessel: I think its a problem with the expansion vessel. Always been a problem, I don't think any plumbers have removed it and tested it when doing the service.
- PRV: I can't tell if this is an issue as there is no tundish, and the pipe is teed into a flow pipe so I can't tell.
So my question is:
- If I top the pressure up to 1 bar today and don't use the heat/water at all for a few days....what would that tell me? (If there is a leak - how long would it take for the water in the system to drain out. I think these systems hold 15 litres max....a leak can be any size, I imagine. So I know it's a 'how long is a piece of string?' question).
If the pressure doesn't drop - does that mean its an expansion vessel / PRV issue? (And if so, why is the HW different from the CH)
If the pressure does drop - does that mean a leak can't be outruled?
- I've seen some suggestions of doing the above, but shutting off the CH outlet and flow (which I think I can do) and also draining it a bit (which I can't / don't want to do)?
Any advice as to how I can narrow this down for the plumber this week would be gratefully welcomed. Thank you.
Have my plumber coming out this week to have a look but wanted to run the following by you guys:
Flexicom 18sx - installed 11 years old. Annual service up to 2 years ago. Problems with pressure drops since the install - we only ever have hot water on (1 hour in morning every day and booster when needed), only put the hear on downstairs during winter whenever needed. Only recently started using upstairs (children getting cold). It's not on that much really.
The normal is - we might need to top up at end of autumn (i.e. after hot water on only during spring, summer). But always need to top up every 4-6 weeks during winter (hot water and heat downstairs) - sometimes longer, sometimes shorter. As I reflect back - I think we need to top up more the colder it is. No one has ever gotten to the bottom of it after each service.
Particularly cold here over the last week and since then the pressure drops to zero after every time we turn the central heating on (which is new - which is why the plumber is coming out). In other words - top up, heat on, heat off, pressure drops <30 minutes.
Friday Night:
- Cold System; topped up to 1bar; no heat/no water on
Saturday AM:
- Hot Water @06:00 - 07:00; pressure stayed at 1 bar.
- No Heat/No Water on all day; Checked pressure at 17:00 (raised to 2 bar - not uncommon)
- CH (Downstairs) on at 17:00 - 18:30; pressure raised to 2.5 bar
- Added CH (Upstairs and Hot Water) from 17:30 to 18:30: pressure stayed at 2.5 bar
- 19:00 pressure dropped to zero; topped back up to 1 bar
- No heat/water on for remainder of night
Sunday AM:
- Hot Water @06:00 - 07:00; pressure stayed at 1 bar.
- CH (Upstairs) 13:00 - 14:00; pressure to 2 bar
- 14:30l pressure to 0 bar. (usually the pressure doesn't drop when the upstairs is used - this is certainly new).
Clearly I have a problem
- Leaks: There's none upstairs, there's none in the hot water system, there may be one in the sub-floor. All radiators have been checked and joints cinched up. I don't think there is a leak - as the issue is not consistent. It fluctuates depending on what is turned on (HW v CH) and even then only the downstairs CH and even then when its colder out (we of course is likely related to frequency of use).
- Automatic Air Vent: Not sure if I have one on the system. There's one on the hot water tank.
- Expansion Vessel: I think its a problem with the expansion vessel. Always been a problem, I don't think any plumbers have removed it and tested it when doing the service.
- PRV: I can't tell if this is an issue as there is no tundish, and the pipe is teed into a flow pipe so I can't tell.
So my question is:
- If I top the pressure up to 1 bar today and don't use the heat/water at all for a few days....what would that tell me? (If there is a leak - how long would it take for the water in the system to drain out. I think these systems hold 15 litres max....a leak can be any size, I imagine. So I know it's a 'how long is a piece of string?' question).
If the pressure doesn't drop - does that mean its an expansion vessel / PRV issue? (And if so, why is the HW different from the CH)
If the pressure does drop - does that mean a leak can't be outruled?
- I've seen some suggestions of doing the above, but shutting off the CH outlet and flow (which I think I can do) and also draining it a bit (which I can't / don't want to do)?
Any advice as to how I can narrow this down for the plumber this week would be gratefully welcomed. Thank you.
Last edited:
