What are the advantages of an outside temp sensor on boiler?

[Doctor Drivel]

One of the best features of the Biasi M110 is that it has weather compensation!

If that is so, then it is one hell of a high specced boiler for the price. Pity the flow rate is not that brilliant.

 

[Doctor Drivel]

I fitted an external WC sensor to my Biasi M110 combi.

Does it have room temperature influence, using a temperature sensor rather than a simple on-off stat.

No, it has several different compensation curves where x/y = outside temp/ CH temp. You select a curve during programming and then the boiler follows that.

So, the room stat works in the normal way - just knock off the burner when the temerature is over setpoint?

 

[mehran]

One of the best features of the Biasi M110 is that it has weather compensation!

If that is so, then it is one hell of a high specced boiler for the price. Pity the flow rate is not that brilliant.

the m110.32 is a 14l/m that can ramp up to 16l/m if given time. i have very interested in the fact that you can get the biasi to work with a homemade wc...really a ntc in a box,

i am guessing that u used a wet type ntc?

 

[Doctor Drivel]

One of the best features of the Biasi M110 is that it has weather compensation!

If that is so, then it is one hell of a high specced boiler for the price. Pity the flow rate is not that brilliant.

the m110.32 is a 14l/m that can ramp up to 16l/m if given time.

Up to 16 l/min @ 35C temp rise? How?

i have very interested in the fact that you can get the biasi to work with a homemade wc...really a ntc in a box,

i am guessing that u used a wet type ntc?

The reaction time of wet and dry temp sensors is different. However as it is sensing outside temps, which changes very slowly, this should not be a problem.

 

[Agile]

i am guessing that u used a wet type ntc?

The reaction time of wet and dry temp sensors is different. However as it is sensing outside temps, which changes very slowly, this should not be a problem.

Actually the response time is little different if the thermal transfer paste is used. Just a little slower with the dry pocket type.

Using an NTC as an outdoor sensor is actually an advantage as it better averages the outside temperature slower and does not respond to gusty conditions where sun heated air may be randomly blown across the sensor.

Thats another advantage of the M110 that you have to use a cheap NTC sensor rather than a manufaturer's sensor at £65 like the other makes!

Its mad that their sales department dont advertise them based on the WC as that would greatly boost their sales. Even most of the Worcesters dont have WC. They still seem to sell a lot of their Band B M96 based on the price and high reliability.

Tony

 

[mehran]

the boiler is under rated in the manual, it will not give 16 out right, it will ramp up to give you the 16 over few minutes. i think a lot of makers do this,
the dhw hx in the m110.32 is a 18l/m hx, as long as the boiler is gas right and the hx's are not blocked it will give you 16, you just have to wait.

i think they say 14 because it gives you the temp quickly and gives biasi some room if the boiler is under gassed or the dhw hx is partly blocked to still give what it said in the Manuel. i think this is common to a lot of makers to under state the boiler because of the ramp up and margins for error.

i would not sell it to a customer as a 16l/m boiler tho

 

[Doctor Drivel]

i am guessing that u used a wet type ntc?

The reaction time of wet and dry temp sensors is different. However as it is sensing outside temps, which changes very slowly, this should not be a problem.

Actually the response time is little different if the thermal transfer paste is used. Just a little slower with the dry pocket type.

Using an NTC as an outdoor sensor is actually an advantage as it better averages the outside temperature slower and does not respond to gusty conditions where sun heated air may be randomly blown across the sensor.

All need be in is a weather proof plastic box laying on the bottom. The outside sensors on commercial compensators actually sense the temperature of the brickwork too.

Thats another advantage of the M110 that you have to use a cheap NTC sensor rather than a manufaturer's sensor at £65 like the other makes!

Its mad that their sales department dont advertise them based on the WC as that would greatly boost their sales. Even most of the Worcesters dont have WC. They still seem to sell a lot of their Band B M96 based on the price and high reliability.

Tony

The tech people probably don't want the hassle of constant calls from people who don't know how to set the compensation up.

On BASIS, what is the most common fault? Is it worth buy the common failure parts in advance, in case.

Does the M110 have a on-off room stat that is separate from the weather compensator.

 

[Doctor Drivel]

the boiler is under rated in the manual, it will not give 16 out right, it will ramp up to give you the 16 over few minutes. i think a lot of makers do this,
the dhw hx in the m110.32 is a 18l/m hx, as long as the boiler is gas right and the hx's are not blocked it will give you 16, you just have to wait.

i think they say 14 because it gives you the temp quickly and gives biasi some room if the boiler is under gassed or the dhw hx is partly blocked to still give what it said in the Manuel. i think this is common to a lot of makers to under state the boiler because of the ramp up and margins for error.

i would not sell it to a customer as a 16l/m boiler tho

I find that the plate heat Xs on combis tend to be undersized. The return from them back to the boiler, even when on full tap flow, tends to quite hot. This indicates it is undersized. A larger plate would improve the flowrate

 

[NGBod]

Does the M110 have a on-off room stat that is separate from the weather compensator.

Yes, the connections for the on-off room stat are separate to the weather comp.
I've used a Honeywell CM927 programmable room stat. The CM927 uses its own outside temp probe to give the optimum start facility mentioned earlier in the thread. I have not enabled optimum start though as I think it may get confused due to the boilers own pre-emptive temp compensation.

Dave

 

[Doctor Drivel]

Does the M110 have a on-off room stat that is separate from the weather compensator.

Yes, the connections for the on-off room stat are separate to the weather comp.
I've used a Honeywell CM927 programmable room stat. The CM927 uses its own outside temp probe to give the optimum start facility mentioned earlier in the thread. I have not enabled optimum start though as I think it may get confused due to the boilers own pre-emptive temp compensation.

Dave

It should be OK. I'm not sure if the Honeywell is self-adaptive, in that it learn the characteristics of the boiler in the environment it is in.

 

[NGBod]

Does the M110 have a on-off room stat that is separate from the weather compensator.

Yes, the connections for the on-off room stat are separate to the weather comp.
I've used a Honeywell CM927 programmable room stat. The CM927 uses its own outside temp probe to give the optimum start facility mentioned earlier in the thread. I have not enabled optimum start though as I think it may get confused due to the boilers own pre-emptive temp compensation.

Dave

It should be OK. I'm not sure if the Honeywell is self-adaptive, in that it learn the characteristics of the boiler in the environment it is in.

Yes, the Honeywell is self adaptive, thats why I thought it might not cope with the boiler also adapting to suit the prevailing weather. They may well work together I'm just not sure.

Dave

 

[Doctor Drivel]

Does the M110 have a on-off room stat that is separate from the weather compensator.

Yes, the connections for the on-off room stat are separate to the weather comp.
I've used a Honeywell CM927 programmable room stat. The CM927 uses its own outside temp probe to give the optimum start facility mentioned earlier in the thread. I have not enabled optimum start though as I think it may get confused due to the boilers own pre-emptive temp compensation.

Dave

It should be OK. I'm not sure if the Honeywell is self-adaptive, in that it learn the characteristics of the boiler in the environment it is in.

Yes, the Honeywell is self adaptive, thats why I thought it might not cope with the boiler also adapting to suit the prevailing weather. They may well work together I'm just not sure.

Dave

The only thing that will fool it is a sharp change in the weather. However many of these devices will adopt another strategy if the outside temperature drops too much and bring in the system earlier. Also the compensator will ramp up the rads temperature anyway.

 

[Doctor Drivel]

However at the end of the day many customers dont want to pay the considerable extra cost to supply and fit the external sensor which is usually grossly overpriced by the manufacturer.

Tony

I fitted an external WC sensor to my Biasi M110 combi.
I couldn't locate a Biasi sensor and rang Biasi technical who at first told me Biasi's didn't support this feature and asked why I wanted to use it. They then said weather compensation is only of use in countries like Sweden.
Later I noticed in the manual that the resistance curve for the weather comp sensor was the same as the heat exchanger NTC's on the Biasi so used one of them. (Cheap)
So far it is working well. I chose a fairly steep compensation curve due to having an old house with poorly insulated solid walls. With an outside temp of 15 degC the boiler sends water to the rads at about 30 degC but with an outside temp of 5 degC it sends the water out at about 60 degC.

Dave

In operation does it reduce boiler cycling? The exhaust must be pluming constantly .

Weather compensation is ideal for the UK with its changeable climate - warm one day cool the next.

 

[NGBod]

In operation does it reduce boiler cycling? The exhaust must be pluming constantly .

Weather compensation is ideal for the UK with its changeable climate - warm one day cool the next.

It has reduced boiler cycling on my system, but fine tuning of which compensation curve is used should reduce it even more. IMO a well matched compensation curve should almost eliminate boiler cycling ie. when the CH flow temp is just sufficient to keep the room temp in the middle of the on- off room stats chosen modulation range.

Dave

 

[Doctor Drivel]

In operation does it reduce boiler cycling? The exhaust must be pluming constantly .

Weather compensation is ideal for the UK with its changeable climate - warm one day cool the next.

It has reduced boiler cycling on my system, but fine tuning of which compensation curve is used should reduce it even more. IMO a well matched compensation curve should almost eliminate boiler cycling ie. when the CH flow temp is just sufficient to keep the room temp in the middle of the on- off room stats chosen modulation range.

Dave

An on-off stat modulates the burner?
Once the compensator dictates that the input is lower the what the burner can deliver, cycling is inevitable. I think it is around 9kW minimum delivery by this boiler.