Boiler/water pressure issues

KaratePigeon

Hi, hoping for some advice as I've been going round in circles with this. 

4 bed semi detached house, a Worcester boiler with a hot water cylinder.

Issues:
1. The main bathroom has a non-electric mixer shower, the low pressure on the hot water makes it very difficult to use for a decent temperature/flow. I'd like to get this sorted as I have 3 teenagers who shower a lot and I'm fed up with 2 of them using my ensuite because of this. 
2. Electric shower in the en-suite, again rubbish pressure but slightly better than the other one. 
3. Sometimes when the heating has been on for a while, it won't turn off, turning off at the timer or the thermostat doesn't work and I have to turn the boiler off to get it to stop. 
4. Boiler hasn't been serviced since I've lived here (2.5 years) so probably should get that done.

The options I've been given for the water pressure issue is to either get a pump put on the top of the water cylinder (£4-500ish) or to get an electric shower put in the main bathroom (would need a cable etc so probably similar price). No suggestions for the en-suite. 

For the heating not going off, the guy thinks its the thermostat but might be a faulty valve. If I'm getting a new thermostat I'd like a Hive/Nest as have been thinking about one for a while, but would need an electrician involved for this so I'm guessing about £300, and hope it's not the valve?

Boiler service maybe another £100 I'm guessing. So do I do all this (must be about £1k?) and still won't help the water pressure in the en-suite as this is just on the cold water.

Or... do I spend £3-4k and get a new combi boiler which will hopefully mean no ongoing maintenance needed for a few years and maybe cheaper bills?

I'm reluctant to replace the boiler when it's generally working fine (also this would be all my savings), but also doesn't feel very future-proof to add things to an old boiler.

ThisIsWeird

Boiler issue most likely a stuck motorised valve - it's the last device in the control chain, and does control the boiler independently, so if the microswitch in there is stuck closed, the boiler will keep running. And it's quite common.
What kind of thermostat do you have? Does it 'click' is a satisfying way? Does it have a display? If so, does a 'flame' symbol appear when it should?
Easy to test using a test meter or volt stick, but something to try is to turn the thermo down until it indicates 'off' - ideally with a satisfying click - and if the boiler keeps running, strike the silver metal case of the motorised valve with a lump of wood

KaratePigeon

The thermostat is a dial stuck on the wall of the living room, looks like it's been there for many years! No display. It does work though, clicks on and turns the heating on when you turn it, and most of the time turning it down clicks the heating off. Just sometimes it doesn't (mostly when i've been lazy and left it too long so the house is already a bit too warm!) Where is the motorised valve, on the thermostat? The boiler is upstairs in an airing cupboard.

ThisIsWeird

For your shower issues, you need to understand what type of water system you have. From what you describe, I'm assuming;
1) Vented hot cylinder, supplied by a CWS tank in the loft?
2) Mains cold water supply to your bathrooms, which would certainly be the case in the ensuite as it has an instant leccy shower? Your bathroom sink basin - how do the hot and cold flows compare?
3) Electric shower in ensuite will always be little more than adequate - that's the nature of instant electric showers. You are probably only getting around 5lpm out of it = pants. So swapping main bathroom shower to instant electric will be equally disappointing, so not the best solution imo. Yes, you could go to the max size of 10.8kW, but still...
4) Don't replace boiler unless it's just about the only solution - it's just an utter waste of money. 
So, what to do? I'm guessing the main bathroom shower issue is down to a combination of the hot and cold supplies being unbalanced (cold from mains - high pressure - and hot driven from tank in loft - low), and possibly the shower mixer not being a thermostatic type.
So, could you confirm as much of the above as you can, please? Also, post a pic of your shower mixer so we can hopefully ID whether it's thermo. For instance, does the temp control have a scale on it, showing '38oC' for example?
IF your mixer is a thermo type, then you might be able to sort the pressure imbalance by adding a tiny booster pump to the hot side - around £100.

FreeBear

ThisIsWeird said: 4) Don't replace boiler unless it's just about the only solution - it's just an utter waste of money.

If water flow is low from an electric shower, switching to a combi isn't going to improve matters. Replacing with another gas boiler is not likely to save much gas. Putting in a new thermostat on the other hand, could see a saving of 5-15% if it is a programmable one. And if the boiler can modulate, a thermostat that can communicate with the WB will save a couple more percent.

If you were to replace the gas boiler, I'd seriously look at a heat pump - The likes of Octopus have been giving out quotes that are comparable to the cost of a gas boiler, and some have been significantly cheaper (under £1K for a few).

ThisIsWeird

FreeBear said:

If water flow is low from an electric shower, switching to a combi isn't going to improve matters. 

I don't understand this.
Electric instant showers are pants due to the limit of power available to them, just over 10kW being the most (and few are that). They are just hellish things, and cannot produce a truly enjoyable soak.
A combi boiler will typically be around three times as effective, a completely different order of enjoyment. 

FreeBear

ThisIsWeird said:

FreeBear said:

If water flow is low from an electric shower, switching to a combi isn't going to improve matters. 

I don't understand this.

Let me put it another way - If your mains water pressure is low, and you only get a slow dribble from the taps, a combi boiler is not going to deliver high pressure water gushing out of any tap or shower.

KaratePigeon

ThisIsWeird said:

For your shower issues, you need to understand what type of water system you have. From what you describe, I'm assuming;
1) Vented hot cylinder, supplied by a CWS tank in the loft?
2) Mains cold water supply to your bathrooms, which would certainly be the case in the ensuite as it has an instant leccy shower? Your bathroom sink basin - how do the hot and cold flows compare?
3) Electric shower in ensuite will always be little more than adequate - that's the nature of instant electric showers. You are probably only getting around 5lpm out of it = pants. So swapping main bathroom shower to instant electric will be equally disappointing, so not the best solution imo. Yes, you could go to the max size of 10.8kW, but still...
4) Don't replace boiler unless it's just about the only solution - it's just an utter waste of money. 
So, what to do? I'm guessing the main bathroom shower issue is down to a combination of the hot and cold supplies being unbalanced (cold from mains - high pressure - and hot driven from tank in loft - low), and possibly the shower mixer not being a thermostatic type.
So, could you confirm as much of the above as you can, please? Also, post a pic of your shower mixer so we can hopefully ID whether it's thermo. For instance, does the temp control have a scale on it, showing '38oC' for example?
IF your mixer is a thermo type, then you might be able to sort the pressure imbalance by adding a tiny booster pump to the hot side - around £100.

1) Yes I have a cold water tank in the loft, that's about as much as I know!
2) Yes mains cold water suppling the bathrooms (as far as I know), the cold water pressure is fine, the hot water flow is rubbish (from basins)
3) Yeah that's what I'm thinking, the shower in there has a label on it saying 2021 so it's fairly modern, not sure an upgrade would help
4) Yeah the plumber said something about the unbalance between the hot and cold and some kind of pump thing that would fix it. The shower mixer I actually installed myself as the previous one was leaking (very proud of this so hopefully I didn't do anything wrong, think it was an improvement in terms of cosmetics and not leaking even if it did nothing for the pressure! this one: https://www.wickes.co.uk/Wickes-Waterfall-Bath-Shower-Mixer-Tap---Chrome/p/212338?gQT=1 Regarding your other suggestion -  when I moved in there was a pump installed on the hot side under the bath. It failed so I got a new one and paid for it to be installed, then after a few weeks that failed too. Apparently it's not a good place for it as air gets it and seizes the pump So the pump is still there actually but it's turned off as otherwise it makes a disturbing squealing noise! 

I've had a couple of different plumber/heating engineers to see what they suggest but they don't seem very confident. 

KaratePigeon

FreeBear said:

ThisIsWeird said: 4) Don't replace boiler unless it's just about the only solution - it's just an utter waste of money.

If water flow is low from an electric shower, switching to a combi isn't going to improve matters. Replacing with another gas boiler is not likely to save much gas. Putting in a new thermostat on the other hand, could see a saving of 5-15% if it is a programmable one. And if the boiler can modulate, a thermostat that can communicate with the WB will save a couple more percent.

If you were to replace the gas boiler, I'd seriously look at a heat pump - The likes of Octopus have been giving out quotes that are comparable to the cost of a gas boiler, and some have been significantly cheaper (under £1K for a few).

Thanks - good to know a combi won't help the water pressure, as the engineer didn't really answer that question. I think they just wanted to persuade me to pay them to replace the boiler! My long term plan is probably to keep my boiler for another 5 years or so then maybe get a heatpump, I'd rather wait until a few of my friends have them first so I can see what they are like! I mentioned this to the engineer today too, and he said nah, heatpumps are never going to replace boilers. (again, not sure I trust him as think it's definitely heading that way!) Though maybe it is worth me getting a quote - would that improve my hot water pressure?! I have a small garden so not sure where the heatpump would go or how noisy it would be, which is what is putting me off. 

ThisIsWeird

FreeBear said:

ThisIsWeird said:

FreeBear said:

If water flow is low from an electric shower, switching to a combi isn't going to improve matters. 

I don't understand this.

Let me put it another way - If your mains water pressure is low, and you only get a slow dribble from the taps, a combi boiler is not going to deliver high pressure water gushing out of any tap or shower.

Ah, I see. I don't think there was any suggestion of poor mains flow, tho'.

ThisIsWeird

KaratePigeon said:

ThisIsWeird said:

For your shower issues, you need to understand what type of water system you have. From what you describe, I'm assuming;
1) Vented hot cylinder, supplied by a CWS tank in the loft?
2) Mains cold water supply to your bathrooms, which would certainly be the case in the ensuite as it has an instant leccy shower? Your bathroom sink basin - how do the hot and cold flows compare?
3) Electric shower in ensuite will always be little more than adequate - that's the nature of instant electric showers. You are probably only getting around 5lpm out of it = pants. So swapping main bathroom shower to instant electric will be equally disappointing, so not the best solution imo. Yes, you could go to the max size of 10.8kW, but still...
4) Don't replace boiler unless it's just about the only solution - it's just an utter waste of money. 
So, what to do? I'm guessing the main bathroom shower issue is down to a combination of the hot and cold supplies being unbalanced (cold from mains - high pressure - and hot driven from tank in loft - low), and possibly the shower mixer not being a thermostatic type.
So, could you confirm as much of the above as you can, please? Also, post a pic of your shower mixer so we can hopefully ID whether it's thermo. For instance, does the temp control have a scale on it, showing '38oC' for example?
IF your mixer is a thermo type, then you might be able to sort the pressure imbalance by adding a tiny booster pump to the hot side - around £100.

1) Yes I have a cold water tank in the loft, that's about as much as I know!
2) Yes mains cold water suppling the bathrooms (as far as I know), the cold water pressure is fine, the hot water flow is rubbish (from basins)
3) Yeah that's what I'm thinking, the shower in there has a label on it saying 2021 so it's fairly modern, not sure an upgrade would help
4) Yeah the plumber said something about the unbalance between the hot and cold and some kind of pump thing that would fix it. The shower mixer I actually installed myself as the previous one was leaking (very proud of this so hopefully I didn't do anything wrong, think it was an improvement in terms of cosmetics and not leaking even if it did nothing for the pressure! this one: https://www.wickes.co.uk/Wickes-Waterfall-Bath-Shower-Mixer-Tap---Chrome/p/212338?gQT=1 Regarding your other suggestion -  when I moved in there was a pump installed on the hot side under the bath. It failed so I got a new one and paid for it to be installed, then after a few weeks that failed too. Apparently it's not a good place for it as air gets it and seizes the pump So the pump is still there actually but it's turned off as otherwise it makes a disturbing squealing noise! 

I've had a couple of different plumber/heating engineers to see what they suggest but they don't seem very confident. 

Thanks - that's all pretty clear.
Electric showers will perform as good as their power rating. Most are around 8.5kW, and that will give a thin spray - it'll get you clean, but never satisfying.
The largest is 10.8kW, so nicely better, but still nowhere close to a conventional shower - and they'll almost certainly require a supply cable upgrade to 10mm2.
With your bath shower, since you have cold mains - higher pressure - and hot from a tank in the loft - low - you'll have a large imbalance which will be hard to control.
The under bath pump makes sense, but you'll need one that does not go kaput.
I wonder if your hot cylinder has a flange in its top HW outlet? Photo, please? If you pump the supply from a vented hot cylinder like yours, it runs the risk of drawing in air from the vent pipe if it struggles to get hot water out fast enough. A solution is a flange - Surrey, or Essex, not sure of the difference - which goes down a bit into your hot cylinder, and draws the water from a few inches down. This keeps the 'suck' nicely away from the vent pipe, so it's unlikely to draw in air. So, that's something I'd be investigating.
Perhaps that'll be enough to balance your shower supply once the pump is up and running again?
But... your shower mixer is non-thermostatic, so will always be a bit of a juggle. That's a nice-looking bath mixer, tobesure, but won't serve you well!