I've just moved in to a new house (built 2003) and it's fitted with a Worcester CDi 35kw combi unit that's about 12 years old (installed with the build). It's got a few problems, it doesn't seem to be able to regulate the DHW temperature properly, so it just goes through the cycle of heating water up to scalding hot, then over-temping, flame cut out, 10 second back-off then re-ignition - which repeats ad-infitum. The result at the tap is water that starts ok, goes scalding hot, then lukewarm and repeat. This is fine for sink/bath use as it still supplies instant hot water for washing hands etc, and if you're running a sink/bath you don't notice the fluctuations in temperature.
Where it is a real problem is the shower - for obvious reasons.
There is one additional factor, I need to add a second shower over a bath to the house, for a lodger. I was originally set on just getting a new combi unit and regular shower, but I keep reading more and more posts online that even high-kW combi units will struggle to adequately supply two showers simultaneously.
I want the most cost-effective short-term solution (money is tight after buying the place - budget is like £2000 tops), I'll be ready to pay for a more long-term solution in a couple of years. With this in mind, I don't want to spend large amounts now, only to change it in a couple of years.
I see my options as:
1. Fit 2 electric showers and live with the boiler as-is for sink/baths. Estimate cost ~£500
Pros - cheapish!
Cons - not a huge fan of electric showers, will require messing up the tiling in the existing shower. Still have old under-performing boiler.
2. Fix the current boiler, install 1 electric shower for the lodger. Estimate cost anything from £300 to £800
Pros - potentially cheapest, depending on repair.
Cons - repair cost hard to estimate, research suggests anything from simple thermistor replacement to long drawn-out sequential parts replacement to find the issue (thermistor, diverter, HEX, gas valve, main circuit board). Then still living with old boiler out of guarantee.
3. Install new higher DHW output (42KW Worcester?) Combi boiler, run two regular DHW fed showers. Estimate cost £1600+
Pros - new efficient boiler, DHW fixed
Cons - not confident that any residential Combi can deliver enough DHW to run 2 first floor showers simultaneously?
What would your expert experienced opinions be on this? - bearing in mind I am willing to save up and invest £5k in a few years time to put in a tank-based system if that is what is really needed.
Disclaimer - I am a competent electronics engineer and domestic plumbing DIYer. I have access to a gas-safe registered heating engineer to do boiler work at 'mates rates'.
Where it is a real problem is the shower - for obvious reasons.
There is one additional factor, I need to add a second shower over a bath to the house, for a lodger. I was originally set on just getting a new combi unit and regular shower, but I keep reading more and more posts online that even high-kW combi units will struggle to adequately supply two showers simultaneously.
I want the most cost-effective short-term solution (money is tight after buying the place - budget is like £2000 tops), I'll be ready to pay for a more long-term solution in a couple of years. With this in mind, I don't want to spend large amounts now, only to change it in a couple of years.
I see my options as:
1. Fit 2 electric showers and live with the boiler as-is for sink/baths. Estimate cost ~£500
Pros - cheapish!
Cons - not a huge fan of electric showers, will require messing up the tiling in the existing shower. Still have old under-performing boiler.
2. Fix the current boiler, install 1 electric shower for the lodger. Estimate cost anything from £300 to £800
Pros - potentially cheapest, depending on repair.
Cons - repair cost hard to estimate, research suggests anything from simple thermistor replacement to long drawn-out sequential parts replacement to find the issue (thermistor, diverter, HEX, gas valve, main circuit board). Then still living with old boiler out of guarantee.
3. Install new higher DHW output (42KW Worcester?) Combi boiler, run two regular DHW fed showers. Estimate cost £1600+
Pros - new efficient boiler, DHW fixed
Cons - not confident that any residential Combi can deliver enough DHW to run 2 first floor showers simultaneously?
What would your expert experienced opinions be on this? - bearing in mind I am willing to save up and invest £5k in a few years time to put in a tank-based system if that is what is really needed.
Disclaimer - I am a competent electronics engineer and domestic plumbing DIYer. I have access to a gas-safe registered heating engineer to do boiler work at 'mates rates'.