QAA 73 Controller

[kilpheder]

I bought a boiler which apparently will only work with the above thermostatic controller. Does anyone have any idea where I can get one. They are advertised for sale by a couple of merchants eg my tub but they are unable to supply. Alternatively can anyone suggest an alternative. Thanks.

 

[ALEC1]

what is the boiler manufacturer?

 

[matt1e]

I bought a boiler which apparently will only work with the above thermostatic controller. Does anyone have any idea where I can get one. They are advertised for sale by a couple of merchants eg my tub but they are unable to supply. Alternatively can anyone suggest an alternative. Thanks.

the QAA 73 is an open therm controller
Any open therm controller with the same features will do

Matt

 

[kilpheder]

It is a trianco optima 28 gas combi.

 

[ALEC1]

geminox/evinox use them...but I think these are "ring fenced"


If you can confirm the boiler is OT then broag have the I sense, Atag the wyse, amd Timeguard have the theben ot controller

 

[kilpheder]

mattie1e the only one that comes up in that definition is the Danfoss ORT-10. Do you think that this would fit the bill? The only problem if this fits the bill is that there is no programmable timer?

 

[matt1e]

Alec has already named a few that are suitable( isense etc )
or Google "opentherm programmable room stat" and go from there
incidentally if you want to go for the siemens one (the QAA 73) then try your local parts centre, your local one is G3 8BW
I would be surprised if you couldn't get one from there, but as said any that are opentherm will work

Matt

 

[Boilerdoctor]

I have this unit in stock

 

[kilpheder]

A QAA 73? and if you have it in stock how much is it going to cost?

 

[Boilerdoctor]

Selected Product: S06985
Quantity Job reference
(optional)
Description QAA 73 PROGRAMMABLE ROOM THERMOSTAT

Manufacturer's product number : BCC/QAA73
Retail Price
(Ex. VAT and quantity discounts) £203.124
Nett Price (ex VAT) £182.81
Nett Price (inc VAT). £219.38

Please note that you CAN use any standard room stat instead of the QAA 73 fust connect to the room stat terminals instead of open therm

 

[ALEC1]

why pn easth do that...OT controls give much better heating systems!

 

[kilpheder]

I can see from the responses that people have provided that I can use a room stat but it does not look as if these units are programmable they just allow thermostatic control or am I missing something?

 

[ALEC1]

The OT controllers modulate the boiler flow temp and offer both a more comfortable environment with few temperature swings, enhanced reliabilty and efficiency..as the flow temperature only ever gets as high as it needs to be to mantain the room temp...


they are worth the extra money...

 

[Boilerdoctor]

I was only pointing out that there are other options.

The QAA 73 is expensive as is the open therm controller quoted by Trianco -about £700 on Parts Center price list. I don't care how good the controller is, in my opinion, is not worth that amount of money. It is also a point to note that it could be a new boiler fitted into an old system and why would you go to the expense of fitting an open therm controller to a 25 year old system.

You would really have to weigh up the options, is it a basic domestic system or do you have other so controls, DHW controls etc ? You can fit a programmable timer, plus a room stat and you probably have individual TRVs fitted as well ? I have seen so many systems that have an open therm unit fitted in say the lounge, great - lounge comes up to temperature and shuts heating down - rest of house is still cool so programmer turned up and lounge TRVs turned down. I've even seen the programmers tuned up to maximum and the TRVs used to control the house temperature so why spend all that money when it's not being used to its full advantage. The same in offices, the programmer fitted in one office (typically the smallest and nearest radiators) so when this reaches temperature every other office freezes. Maybe it's me being cynical but I'm just no convinced they are as good as everyone thinks. Great from a sales point of view but not for the engineer that has to then try and explain to the customer that the unit detects the temperature where it is fitted and controls to that point irrespective of the rest of the building.


You can get programmable room stats, you can also get wireless ones. It really comes down to your budget and how much you are prepared to spend. This plus the efficiency of your actual system - is it new or is it just a boiler upgrade ? There are many controls on the market nowadays including programmable individual thermostatic radiator valves. All down to budget at end of the day.

I personally have a Strata 1/38 Combi boiler with an RE 2132 room unit, a remote room sensor in hall (allowing both all and lounge to dictate the flow temperature and an outside sensor for direct on boiler weather compensation, I also have a cylinder (for a power shower) with cylinder stat fitted and wired to override the outside sensor and give DHW priority on the cylinder, then switch back to compensated heating circuit. My gas bills have dropped considerably over past two years due to the controls as well as fitting cavity wall insulation.

 

[ALEC1]

well we dont have all the information about the site, but if an OT controllers saves 5% then that coild easily be £100 pa....

some manufacturers of compensation OT controls say around 15% savings are obtainable , and this matches my observtions where I have installed these....