My new Ultra

Brad Barbeau

At 4:30 on Friday we turned on our new Ultra 155.  The system is totally new (we had forced air previously) using reclaimed cast iron rads.  It's working  beautifully so far!  I'm playing with the curve a bit and also don't know if I should use the modulating output from the Honeywell AQ (opinions?).  The contractor hadn't used that control before so they don't really know. 

This morning we were running at about 125 degrees (outside is 39 ish), tonight will be a good test because it's supposed to go down to -15. 

I'm interested in your opinions on the install.  We were decided to go with the Ultra over the Vitodens mainly because it modulated lower which was important because of the the way the load is split up (two buildings, one online now, the other will see lower use most of the time when brought online).

Jean-David Beyer

Honeywell AQ

Bear in mind that I am not a professional.



It is not clear to me why you would want such a thing, when the Ultra boilers come with an outdoor sensor to control the resets already. And the controls in the Ultra enable you to adjust the reset curves (if you use more than one) with essentially total flexibility. How would you use the output of the device anyway? Would you use an electrically controlled mixing valve of some kind? I think you could get some serious system stability problems if you tried to have two independent components of your system acting at cross purposes.

SpeyFitter

Grundfos Alpha?

It's too bad your installer didn't use (1) Grundfos Alpha Variable Speed ECM Pump with zone valves instead of 4 regular Grundfos pumps, for zoning. This might have influenced the price down ever so slightly, but more importantly it would have cut down the electricity usage of the system, and could potentially make the heat source operate slightly more efficiently as well.

Brad Barbeau

Agreed

The AQ I have (AQ25A42B) doesn't do outdoor reset, it only uses the outdoor sensor to display the temperture on the thermostat screens.  The advantage it had over the Taco was that it provided zone syncronization which I believe avoids short cycling and included pump exercise (both were the same price).  I'm not sure exactly what the modulating output does but I have the idea that the controller knows which zones could require more heat and passes that on to the boiler?  Anyone know what it really does?

I had wondered about the zone valves after that post last week about ECM pumps.  They thought that pumps were better than valves because of redundancy (this despite the fact that the boiler pump has no redundancy).  When I add the other building on, I'll probably do it with an ECM and valves and if that works well eventually change this stuff over.  We are so happy to finally be warm though!

Brad Barbeau

On the other hand,

I suppose I could just change out pumps eventually, while it would cost a lot more it would be easier because it looks like those are drop in replacements (?). 

Jean-David Beyer

Ultra controls

You may find that reading the installation manual for your boiler to be very educational.



Your Ultra 3 has circulator exercising built in, but not enough for your system. It can exercise the three circulators connected to the boiler. These are usually the boiler circulator, the domestic hot water circulator, and one zone circulator. It also has some freeze protection, provided your gas and electricity are working. When the boiler water gets below 40F, the boiler goes on low fire, and the circulators you specify are run until the temperature gets up to 45F.



Normally a thermostat or aquastat is connected to one of the three thermostat inputs on an Ultra 3. I do not know where you would connect reset information.

Brad Barbeau

Modulation not reset

The AQ has an output that provides a 0-10V signal to the boilers 0-10V input that can drive the modulation.  The boiler manual has this:

The U-Control module provides terminals to input a remote 0–10 VDC

operating signal. This can be provided by a separate controller if the

boiler is configured as Type 4 (SHADOW boiler mode).

2. Connect the 0–10 VDC signal positive terminal to P15 terminal 6, and

the signal common to terminal 5.

3. When receiving a remote operating signal, the boiler starts when the signal

exceeds 1.0 VDC (and shuts off if the signal drops below 0.5 VDC).

The boiler remains at low fire until the signal exceeds 2.0 VDC. Between

2.0 and 10.0 VDC, the boiler firing rate increases with the signal value,

reaching full input at 10.0 VDC.

4. The U-Control continues to monitor boiler temperatures, based on

the values set up under Priority 1 operation. See the following section

for details.

After reading this I'm pretty sure I don't want to use this but I'm not sure who would!  U-Control is handling both the modulation and outdoor reset and seems to work well. 

Jean-David Beyer

Remote modulation.

I think that is used for when twinning, tripling, quadrupling, Ultra boilers so they fire all at the same rate, the rate of the master boiler. I, as a non-professional, do not think you would want to drive this from a thermostat, no matter how clever, because it is involved intimately in the way the boiler is controlled. It gets its input from the sensor at the beginning of the secondary loop if you are heataing the house, or from the sensor(s) at the output of the heat exchanger if you are heating an indirect water heater. The boiler really has to know the temperature of the water leaving the boiler and the temperature returning for safety and efficiency reasons. If you supercede this with something else, you will still have to control the water temperature of the boiler by other means, and since the Ultra controls the temperature by controlling its firing rate, a can of worms would be opened. It may be possible, but remember one of Murphy's laws: When you open a can of worms, to recan them takes a larger size can.



Since this is a heating venue, here is another one I like:



Murphy's Law of Thermodynamics: Things get worse under pressure.

NRT_Rob

AQ controls

I'm pretty sure at least some, if not all, of the AQ controls do indoor temperature feedback like the Tekmarnet 4 controls do.



I don't use the line myself so I can't swear to it. But if I'm right it's ability to modulate the boiler would be far improved over basic outdoor reset only.



I would be more curious why advanced controls are on a project without someone on the project knowing why they are there? that's kind of odd?

bob eck

Ultra

Did you run Viega Fostapex out to the radiators? did you do a home run to each radiator? how did you run to the radiators and how many? Happy heating with your new boiler.......:)

CMadatMe

Honeywell IQ

Unless you plan on using the IQ thermostats and want phone access to them,  want to use indoor reset in addition to outdoor reset or  need to go with Wireless thermostats makes no sense to use it.

Brad Barbeau

Piping

Bob,

Thanks! Actually, it's Uponor hePexPlus I believe. Home runs to each rad from a manifold from each zone.



First floor rads were easy because the basement is unfinished. Iron pipe from the rad to below the floor where it connects to the pex. Second floor was more difficult but there was two ducts that were from the forced air that they used for chases as well as as plumbing chases for three rooms at the back. There was only one room where we had no way in and decided to leave it exposed (iron again), once it's painted it will blend in.



We ended up with 14 rads, all but one came from Ironworks Radiators in Toronto (http://ironworksradiators.ca/). I can't say enough good things about them - the prices are great (seriously, a fraction of anyplace else). They delivered them to us for a very reasonable amount and we're three hours from Toronto. All were pressure tested and we had not one problem with them (touch wood). I expect were one of them going to leak, it would have done so by now. I didn't get them stripped although I now wish I had one or two of them done but that's minor. Fittings were an adventure because many of the rads were different almost all left hand thread which initially caused me minor heart palpitations when I realized how much bushings and valves were going to cost. We eliminated the valves and went the l/r nipples which was much better (the valve, elbow, and bushings were going to exceed the cost of each rad). I did most of the fittings from the first floor to the basement which was interesting (I've not worked with 'real' pipe before). Getting the rads lined up with the holes and the pipes threaded through them was quite a chore - it was nothing to burn 15 minutes per rad doing that.



Our contractor arranged for a heat loss to be done by an engineering firm and from that I calculated the EDR for each room. I tried to get each rad to be 150% of the required BTUs so that we can run at a lower temp (160). So far I'm pretty impressed that I got them so close because it seems that each room is the same temperature. Looking forward to tonight when it gets cold to see how it works!

Brad Barbeau

Simple answer!

I asked for those controls and they said yes. Price was the same as the Taco and it looked to provide more bank for the buck. They do seem to be working well so far - I was mainly interested in the zone synchronization which it does well. I'm also fond of Honeywell stuff.



The AQ manual says this about the modulating output:

The 10 Vdc terminals (15 and 16) of the AQ25A produce a

modulating (0-10 Vdc or 2-10 Vdc) signal that can drive a

modulating boiler’s combustion fan to maintain a constant

supply temperature from the boiler (generally equal to the

Boiler High Limit setting in the EQUIPMENT SETUP > BOILER

SETTINGS sub-menu).

Boiler Signal: If the AQ25A panel is configured to send a

0-10V or 2-10V signal to a modulating/condensing

boiler, connect the AQ25A’s modulating output terminals

(15 and 16) to the modulating signal input on the boiler

control.



I'm not sure that I would want it to do that though since the panel I have doesn't do ODR and it would try to drive to 180 all the time which would override the boilers ODR?

NRT_Rob

sounds like that's adjustable

but if it's fixed temp it's not good. Sounds like they are just giving you a point remote from the boiler with which to control modulation which is useful in some piping configurations.



I'm pretty sure they have indoor feedback options though and that would be the real use for sending a modulating signal. indoor feedback rocks.

Jean-David Beyer

indoor feedback rocks.

Technically, a normal on-off thermostat is already indoor feedback. When the room is too hot, the heat is turned off, and when it is too cold it is turned on.



So I assume you mean proportional indoor feedback instead of simple on-off feedback.



I had an air conditioner in a computer room that had proportional feedback for cooling. It was supplied with chilled water at 40F that went through a chilling coil. The thermostat did not have a microswitch, but a finger that rode up and down on a potentiometer. The output of the potentiometer controlled a valve whose opening was dependent on the potentiometer setting. Actually, it was a three-way valve so that the water flow through the unit was the same no matter what the temperatuer was. This had a range of about +|- 2F. If the room was way too hot, the valve was fully open. If the room was way too cold, the valve was fully closed. As the temperature got into the desired range, the valve would be modulated in between. This permitted quite accurate temperature control.



Now on my boiler, there is no place to hook such a thing, as a practical matter. It has three thermostat inputs in a priority scheme, but they are the usual on-off thermostats. Proportional indoor feedback could be achieved by using an electrically controlled mixing valve such as Taco iSeries-R ones. They require the thermistor type sensors, though, not the 0-10 volt ones. This might not result in customer acceptance, since you might, depending on how aggressive your reset ratio was, have to diddle the mixing valve to change the room temperature. But if the customer was not one who diddled the thermostat settings all the time, it could work.



This does not seem to me to be a simple add-on thing. It looks as though the entire system must be designed to use it up front. Otherwise you could get confusing limit-cycle oscillations in the control system's operation as the boiler's outdoor reset acts at cross purposes with the indor reset.

NRT_Rob

indoor feedback

I mean to indicate water temperature control that is responsive to indoor temperature conditions. advanced controls like AQ or tekmarnet 4 will translate that into a mixing valve control signal or a 0-10v input to run a modulating boiler.



it does require proprietary thermostats though which can report back data to the central controllers.

Jean-David Beyer

Can you explain what happens...

Can you explain what happens when the outdoor reset and the indoor reset both try to adjust the temperature of the water?



Let us say that the outdoor reset (sensor on north side of buildnig) thinks it is cold out, so it increases the boiler supply temperature, but the sun just came out and a room is getting warmer because of the incoming sun, so it wants the supply water temperature reduced. You cannot just leave this to chance; some arbitration must be provided. One extreme would be to disable the outdoor reset. The other extreme would be to disable the indoor reset. Both would be disappointing. Perhaps one could have a large reset ratio for one of them, and a small reset ratio for the other. But this does not seem very satisfactory to me (as a non-professional).



What do professionals do when a client wants both outdoor and indoor reset?

NRT_Rob

outdoor reset is base

indoor feedback adjusts outdoor reset base temp. indoor feedback wins. I'm much more familiar with tekmarnet4, in which the goal is to run the system as constantly as possible with the lowest water temp possible and indoor feedback is used to ensure that.



honestly I don't know why indoor feedback systems even bother with outdoor reset other than to provide a "starting point" for the calcs, but with a good indoor feedback algorithm and decent sensing you *should* in theory be able to start from an aribitrary water temp target number (say, room temp plus some number based on an emitter type) and do almost as well.

Jean-David Beyer

Thank you for your explanation.

I find outdoor reset is a great improvement over no reset, because I have radiant tubing in the concrete slab of my house. Without reset, the slab gets too hot most days, so after the thermostat says "enough" the slab keeps heating the house for 4 to 6 more hours, causing severe overshoot. With outdoor reset, I can diddle the reset so that the slab is just about what is needed to keep the house comfortable. The reset usually infers, from the outside temperature, what the indoor temperature is likely to be and adjusts the heating rate appropriately. This works best when I have the reset such that the circulator is runnng most of the time; I try for 18 hours a day, but when it gets quite warm out, my boiler will not modulate down far enough.



It seems to me that indoor reset, if properly implemented, could help with some other conditions. In cases of very high winds, my house leaks more than at other times, and the indoor sensor would notice this before the outdoor sensor would, and thus control the indoor temperature a little better. Similarly, if the sun came up and dumped a lot of heat into my house before the outdoor sensor (on the north wall where it would not see the sun) would not notice until the outside air temperature rose. I notice this on warm days that follow cold nights. Indoor reset could lower the water temperature sooner and perhaps avoiding having the thermostat cut off the heat entirely. Now where I am, and the experience I am getting, this is not enough to make me add indoor reset, but if my house leaked more, or if my windows allowed much more energy to come in from the sun, it certainly would make sense.

NRT_Rob

it is pretty great though

can raise water temperatures to react faster too if necessary. excellent for high mass systems.