Flow Energy - Boilers

Legacy_user

Flow Energy has been trying to market its electricity-generating boiler for some time. I now see that they have expanded their range by re-badging/selling the Intergas RF Eco boiler. I would be interested to know if anyone has had dealings with this Company as the Intergas RF Eco has piqued my interest as a suitable boiler replacement?

zeupater

Hengus wrote: »

Flow Energy has been trying to market its electricity-generating boiler for some time. I now see that they have expanded their range by re-badging/selling the Intergas RF Eco boiler. I would be interested to know if anyone has had dealings with this Company as the Intergas RF Eco has piqued my interest as a suitable boiler replacement?

Hi

Looking at the seasonal efficiency it looks to be a standard A rated boiler .... ( http://www.ncm-pcdb.org.uk/sap/pcdbsearch.jsp?pid=26 ) .... with RF control, so similar to a number of other brands and models, so it's just down to personal choice - however, having never heard of the company or product before I just looked, the main question I'd be asking would relate to spares availability in UK distribution along with the likelihood of coming across suitably trained engineers if/when needed ....

HTH
Z

System

zeupater wrote: »

Hi

Looking at the seasonal efficiency it looks to be a standard A rated boiler .... ( http://www.ncm-pcdb.org.uk/sap/pcdbsearch.jsp?pid=26 ) .... with RF control, so similar to a number of other brands and models, so it's just down to personal choice - however, having never heard of the company or product before I just looked, the main question I'd be asking would relate to spares availability in UK distribution along with the likelihood of coming across suitably trained engineers if/when needed ....

HTH
Z

Thanks. It is an Intergas boiler in all but name and Intergas has a large distribution, training and technical support facility near Dudley. There are 20 or so accredited Intergas installers within 15 miles of where I live (somewhat surprising since I live about 8 miles from the WB boiler manufacturing site)

Flow uses what it terms 'Ambassadors' to install and maintain its re-badged boiler. I am getting two further quotes from independents, so it will be interesting to see how they compare. I am also getting a couple of Viessmann quotes. I would choose either a WB or Valliant boiler if they supported Opentherm which is now a mandatory requirement in The Netherlands. I have Evohome so there is some logic to my thinking.

zeupater

Hi

So you've effectively got a zoned system through centralised RF control of individual radiators through the Honeywell system and are looking to take the route of controlling boiler modulation to balance heat supply to demand via the control system as opposed to the boiler doing the same either through comparative self modulation or modulation with weather compensation ?? ....

I like the idea from a technical viewpoint, although it doesn't suit our setup at all, but I have serious doubts whether the system would deliver any realistic comfort or financial advantages over a much simpler solution such as a programmable thermostat with TRV setup, either with or without weather compensation .... further to this I certainly wouldn't plan to replace a decent efficiency existing condensing setup unless totally necessary ... I'd also be extremely wary of any claims of efficiency increases referred to as 'up to', particularly ones monetising potential saving in bands of 'up to' 10%, 20%, 30% & 40% ... as they might as well add 'up to 100%' for all they're worth, especially so when decent condensing boilers would have a seasonal efficiency limiting the average maximum potential savings to ~15%, which in itself is more than totally unrealistic - it's impossible! ...

The normal approach to such projects would be would be to concentrate on the primary solution and then address automation, but it seems that here we have a case of the tail wagging the dog ... of course, if money & money saving is no issue then why not!

HTH
Z

System

Yes - I already have Evohome (now 3 years old). I need to replace an old conventional boiler so it makes sense to look at Opentherm. I appreciate that the savings are not going to be great as I have already reduced my gas consumption by 20% just by installing Evohome, and we are a lot warmer in the rooms that we use than we were. I agree an option would be a condensing boiler plus weather compensation but Opentherm does all of the above plus more. Opentherm eliminates the need for weather compensation as Opentherm adjusts the gas valve based on aggregated heat demand. As described on The Evohome Shop website:

The standard way to control a heating system is to switch the boiler on and off at certain intervals with On/Off or TPI controls. OpenTherm provides more precise control on the boiler through the control of the gas valve. It allows the amount of heat provided by the boiler to be controlled to match the varying demand requirements. By reducing the flow temperature to a minimum as it leaves the boiler, OpenTherm modulation helps the boiler efficiency by running at lower flow temperatures for longer periods; this ensures more of the heat exchanger is at condensing temperatures.

To give you a point of reference and an easier way to understand how OpenTherm works here is a real life example:

Imagine two cars at a set of traffic lights. When the light turns green, one of them speeds off as fast as possible while the other drives steadily and sensibly. By the time they reach the next set of lights the sensible driver has caught up and has consumed far less fuel and therefore saved money. Also the fast car has not benefited at all because both cars are now in the same position. In this example the inefficient speedy driver is similar to an ON/OFF control system where as the steady, efficient driver is similar to OpenTherm.

I just need to find an installer whose eyes don't glaze over when smart controls are mentioned.

zeupater

Hengus wrote: »

.... The standard way to control a heating system is to switch the boiler on and off at certain intervals with On/Off or TPI controls. OpenTherm provides more precise control on the boiler through the control of the gas valve. It allows the amount of heat provided by the boiler to be controlled to match the varying demand requirements. By reducing the flow temperature to a minimum as it leaves the boiler, OpenTherm modulation helps the boiler efficiency by running at lower flow temperatures for longer periods; this ensures more of the heat exchanger is at condensing temperatures ....

Hi

Possibly, but probably not as bad as it first looks ....

If the boiler is really old then it will be full power or off as you describe, however any decent modulating boiler will likely address almost all of what you're looking to achieve.

The control you have effectively creates a multi-zone heating system with individual room thermostatic control which isn't really compatible with a non-modulating boiler which would (/should) originally have been sized to provide heat to all radiators until a central thermostat reaches it's set point and cuts out. What effectively happens is that creating zones with different temperatures progressively shuts down demand which causes the boiler to cycle on an ever increasing frequency (on/off) until a central thermostat reaches it's set-point & shuts the boiler down. Modulating boilers address the variable demand issue created by zoning (TRV or otherwise) by monitoring the feed and return temperature differential and then adjust the burners in order to maintain efficient operation within the condensing mode as long as possible ..... our boiler can modulate heat provision from ~30kW down to ~8kW (from memory) and maintain continuous burn operation even when TRVs vary demand.

When looking to maximise efficiency many simply reduce the flow temperature without considering the delta-T effect on radiator heat transfer ... a ~20C room with a flow temperature of ~40C has a delta-T of 20, however the radiators would (/should) have been sized for a delta-T of 50 (ie flow 70C), therefore find that even when the 'cooler' rooms have all (finally) reached set-point, the main living areas struggle to reach a comfortable temperature unless the radiator panels are up-sized .... this is a very similar situation to replacing a gas or oil boiler with a heat-pump (no UFH) without addressing radiator size. Weather compensation is supposed to vary the flow temperature (according to some form of flow/return delta-T and a further internal/external ambient conditions delta-T estimated demand algorithm) in order to increase efficiencies, however, I'd be surprised if the additional cost of this functionality would ever show a return in all but the very coldest regions of the UK. This is very similar to what the 'OpenTherm' is supposed to do, so, apart from it being an 'open' standard (?) as opposed to manufacturer proprietary and/or 'other' standard, I can't really see a technical advantage of having 'external' modulation control over 'integrated', certainly not one which is significant enough to warrant the dismissal of the majority of the brands/models from a sourcing decision ... (other than 'high-claim' & 'well worded' targetted sales literature!)

Ourselves, well we have a standard high efficiency condensing boiler without weather compensation, but it hardly ever gets used other than as a backup for solar thermal DHW or in really cold conditions - so it's set to a standard 70C flow to achieve 60C DHW.

By the way, with any form of modern A-rated modulating boiler the analogy provided becomes irrelevant.

HTH
Z