How reliable are Dimplex Duoheat SH controls?
- by that I mean the plastic control panel AND the PCB
Anyone know the cost of replacement controls?
- just so I know if infected by "crap gas boiler PCB disease"
I will phone Dimplex tomorrow if time to find out.
I was going to buy my mother 1-2 Rinnai 308 gas wall heaters.
Only to heat the hall & bedrooms to 15-16oC (she can't tolerate >18oC).
Other rooms have gas fires - 2 new ones now with FSD.
Occupied 24/7 - housebound, reliability critical, cost secondary.
Gas heating is out due to house layout (too old for the mess, solid floors, house is L shaped on different floor levels & ceiling levels, it would need half the house gutting).
However some initial improvements suggest a rethink.
Findings...
1. Loft AND Walls now insulated - massive difference.
- Hall 3.3kW AutoSH on MAX
- Hall Maxol Montana 2000 gas wall heater on MIN
Coldest bedroom got down to +14.6oC by 11pm, at the end of the long 1oC-day / -5oC overnight period, temperature measured 45cm above the floor (room below unheated for week as worst case).
So baseline background heating WITH insulation is almost ok.
2. Maxol Montana wall heater removed for CWI fitting
- Parts difficult to source as discontinued
- CWI revealed damaged flue, BG installed piping leaking
Rinnai a superior heater but I'm wary of 1) parts cost particularly re forex 2) maintenance cost 3) risk of Rinnai leaving the UK market 4) potential fan noise re bedrooms. Thermostatically controlled gas wall heaters CAN be noisy as they heatup/cooldown (clanking, ticking).
3. Gas wall heaters aren't that efficient
Taking Maxol 2kW on MIN is ~800W is ~62% efficient, using Baxi data.
- Thus 4.64p gas becomes 8.10p on MIN & 6.67p on MAX (75% efficient)
- Add in maintenance cost & replacement cost and it gets worse
Rinnai efficiency better, 5.3p, but higher capital/parts/maintenance.
If you use few gas units, you pay a higher figure re standing charge (it is priced in whatever tariff you choose if domestic).
Hence gas condensing boilers dominate over wall heaters
OPTION-1
- add 2.5kW SH to the existing 3.3kW SH
- add 800-1000W thermostat timed 2pm-12pm heater on hall landing
SH MAXIMUM cost over 100 days (100% charge) = £210 (sod all)
Panel MAXIMUM cost over 100 days (2pm-12am) = £100 (10hrs)
Total is £310 for 4895kW - very unlikely even if 2008 1996 winter.
OPTION-2
- two 2.55kW Duoheat 2.55kW SH & 0.5kW Panel combined
- more complicated (reprogram annually as On-Nov Off-Feb)
SH MAXIMUM cost over 100 days (100% charge) = £189 (sod all)
Panel MAXIMUM cost over 100 days (12pm-12am) = £150 (12hrs)
Total is £339 for 4770kW - very unlikely even if 2008 1996 winter.
I like Option-1 because it is *simplicity* & *reliable*.
- Reliable electromechanical SH controls & turn on/off - 25yr life.
- It's a resistor & bricks - failsafe, doesn't get much simpler.
I like Option-2 because of the "integrated heating",
- BUT I am wary of crap PCB design/quality/heat - 5yr life.
- This adds marketing fiddling with engineering costs.
Duoheat no doubt uses thermistors for temp sensing, which might actually mean it does better than capillary thermostats. Drugasar gas wall heaters without a modulating & poorly positioned capillary sensor clank & bang as the thing cycles without hysterisis dampening
Relative screwed on boiler maintenance contract (contract never put enough inhibitor in, boiler trashed, whole system corroded, bill well into 4 figures & no spares for the boiler now). So wary of "sell product cheap, many money on training/service".
Quite WHY Dimplex didn't do two dials on the heater is bizarre.
Why change a "background temp & comfort temp 2 dial" control?
One remaining trick would be "porch doors" since the hall has huge leaded windows although sheltered. That really needs an offset hinge (a la commercial) to avoid tiny doors or a door that swings open or too big to swing inwards. That would knock most of the remaining heatloss on the head.
House designer lived in & built cornish cottages, so you can imagine the "which b@stard laid this house out re walls/space".
- by that I mean the plastic control panel AND the PCB
Anyone know the cost of replacement controls?
- just so I know if infected by "crap gas boiler PCB disease"
I will phone Dimplex tomorrow if time to find out.
I was going to buy my mother 1-2 Rinnai 308 gas wall heaters.
Only to heat the hall & bedrooms to 15-16oC (she can't tolerate >18oC).
Other rooms have gas fires - 2 new ones now with FSD.
Occupied 24/7 - housebound, reliability critical, cost secondary.
Gas heating is out due to house layout (too old for the mess, solid floors, house is L shaped on different floor levels & ceiling levels, it would need half the house gutting).
However some initial improvements suggest a rethink.
Findings...
1. Loft AND Walls now insulated - massive difference.
- Hall 3.3kW AutoSH on MAX
- Hall Maxol Montana 2000 gas wall heater on MIN
Coldest bedroom got down to +14.6oC by 11pm, at the end of the long 1oC-day / -5oC overnight period, temperature measured 45cm above the floor (room below unheated for week as worst case).
So baseline background heating WITH insulation is almost ok.
2. Maxol Montana wall heater removed for CWI fitting
- Parts difficult to source as discontinued
- CWI revealed damaged flue, BG installed piping leaking
Rinnai a superior heater but I'm wary of 1) parts cost particularly re forex 2) maintenance cost 3) risk of Rinnai leaving the UK market 4) potential fan noise re bedrooms. Thermostatically controlled gas wall heaters CAN be noisy as they heatup/cooldown (clanking, ticking).
3. Gas wall heaters aren't that efficient
Taking Maxol 2kW on MIN is ~800W is ~62% efficient, using Baxi data.
- Thus 4.64p gas becomes 8.10p on MIN & 6.67p on MAX (75% efficient)
- Add in maintenance cost & replacement cost and it gets worse
Rinnai efficiency better, 5.3p, but higher capital/parts/maintenance.
If you use few gas units, you pay a higher figure re standing charge (it is priced in whatever tariff you choose if domestic).
Hence gas condensing boilers dominate over wall heaters
OPTION-1
- add 2.5kW SH to the existing 3.3kW SH
- add 800-1000W thermostat timed 2pm-12pm heater on hall landing
SH MAXIMUM cost over 100 days (100% charge) = £210 (sod all)
Panel MAXIMUM cost over 100 days (2pm-12am) = £100 (10hrs)
Total is £310 for 4895kW - very unlikely even if 2008 1996 winter.
OPTION-2
- two 2.55kW Duoheat 2.55kW SH & 0.5kW Panel combined
- more complicated (reprogram annually as On-Nov Off-Feb)
SH MAXIMUM cost over 100 days (100% charge) = £189 (sod all)
Panel MAXIMUM cost over 100 days (12pm-12am) = £150 (12hrs)
Total is £339 for 4770kW - very unlikely even if 2008 1996 winter.
I like Option-1 because it is *simplicity* & *reliable*.
- Reliable electromechanical SH controls & turn on/off - 25yr life.
- It's a resistor & bricks - failsafe, doesn't get much simpler.
I like Option-2 because of the "integrated heating",
- BUT I am wary of crap PCB design/quality/heat - 5yr life.
- This adds marketing fiddling with engineering costs.
Duoheat no doubt uses thermistors for temp sensing, which might actually mean it does better than capillary thermostats. Drugasar gas wall heaters without a modulating & poorly positioned capillary sensor clank & bang as the thing cycles without hysterisis dampening
Relative screwed on boiler maintenance contract (contract never put enough inhibitor in, boiler trashed, whole system corroded, bill well into 4 figures & no spares for the boiler now). So wary of "sell product cheap, many money on training/service".
Quite WHY Dimplex didn't do two dials on the heater is bizarre.
Why change a "background temp & comfort temp 2 dial" control?
One remaining trick would be "porch doors" since the hall has huge leaded windows although sheltered. That really needs an offset hinge (a la commercial) to avoid tiny doors or a door that swings open or too big to swing inwards. That would knock most of the remaining heatloss on the head.
House designer lived in & built cornish cottages, so you can imagine the "which b@stard laid this house out re walls/space".
