I need some help with my Radiant system in my 1 year old home in the Monterey Peninsula area of Northern California.

Our radiant installer has been a bit of a pain since day 1 and I want to make sure I get any proper maintenance and possibly even have some updates done to our system (don't want to use this installer).

Our System:
Polaris 50 Gal NG Condensing Water Heater
1500 sq. ft of concrete slab 1st floor with Pex and 5 zones of varying length
1500 sq. ft second floor with radiant panels all on 1 zone

The Polaris is in a un-insulated outdoor storage closet attached to the side of the garage. It is piped as a closed system with heat exchange unit for the Domestic Heat, and provides Domestic Hot Water as well. We have never had the hot water run out on us with up to 5 people in the house, so that is a plus. The closet does heat up pretty good when the heat is being called for. We have been running it for 1 year and with some minor hiccups here and there - overall it is working - I just think it could work better, and want to make it work as good as we can, especially if there are some simple changes that could be made.

We don't have an outdoor reset circuit, but in our mild climate (Zip 93940) it wasn't recommended for us.  Our local city and the CalGreen building codes were pretty strict, so we have at least a moderately efficient house.   We have only one closed loop heat supply from the heat exchager for both types of heat (slab and radiant panels).  Our 2nd floor has lots of glass (coastal living!) with no window coverings, so we had problems getting the house really warm on cold cloudy (35 deg F) mornings and evenings.  It would seem to just sit at 66deg...My installers response to this was to turn up the Polaris temp, thus putting out 135deg water to the HX and thus to all zones.  Now we can get up to 70deg after a few hours (we have the upstairs thermostat setback at 65F and have it set to 69F 90mins before we wake up). This seems like it might be a solution for the upstairs, but I am worried about the higher temps for the slab.  We haven't had any overshoots on the slab, and it is pretty comfortable.  But we keep everything between 65-67 on the thermostats for the slab.  The mini thermometers on our Rehau pro-balance zone manifold show 130F incoming and I think 100F outgoing (I need to double check this again).

Should we be doing any maintenance on the Polaris yet?
How can a closed loop system have a mixing valve added to lower the temperature for our slab section or is it needed?
Our Gas Use is pretty good ~ an extra $100 for the month of December over a month with no heat, so we don't want to spend a bunch of money to save $5-10 per month.

Thanks in advance (and I am sure I got plenty of things wrong and missed many correct terms in my post - so sorry in advance for that),
Woody

edit: I am going to get some more details about my system and report it back here - I think the pumps might be running a bit high (he has them set on medium) and I also want to get exact Delta T numbers and my zone pex lengths etc... so there is more to come from me...

What sort of radiant panels on the second floor?

The original heat load would dictate both the size of panels needed and the design (delivered) supply temperature for each system.

Why is the Polaris outside?

Runtal Radiators (4 of them are upstairs).

The utility room is outside the envelope of the house based on the original house design (in a seperate 2x4 framed closet/room)  I could insulate this and was planning to....

It is at a very central location central to all of our bathrooms, kitchen and laundry.

The size of the Runtals - and the design load was calculated by several industry people - including a Manual J, a "rule of thumb" by the heating installer, plus the required energy calc spreadsheet for Calif etc...I think they all came out pretty similar.

Our design day heat load for both the Slab and the Upstairs combined was 35,000 Btu/hr if I remember correctly (20k slab, 15k upstairs)

When designing combi space and domestic hot water heating systems we most often use a condensing water heater and more often then not, a Polaris condensing water heater. Sometimes wel have to employ a multi-temperature delivery system, but this is never ideal as it costs more to install and maintain.

Putting PEX in a slab should be mandatory, but the upper levels are always a struggle since they often require higher design temperatures and the relative cost is more than twice the cost of a radiant slab. To get the upper floor radiation ( be it radiant floors, ceilings, walls or panel radiantors like yours), the best and most simple design is to over-size the panel radiators to allow lower water temperatures.

It seems yours are a bit over-sized, but if your average temperatures are fairly narrow, it is no sin to run a bit hotter than the perfect design temperature. If your system does not get behind nor overshoot and you are comfortable, no one can substantially improve on this, given your moderate heat demands and heat source.

But, we would have used outdoor reset to lower the average water temperature, increasing run time, improving comfort and lower operating costs at the same price. You should find a new friend in the industry and make sure they know how to clean and treat the boiler water for long life and continued efficiency.

It seems like your system is working fairly well.The Polaris is a good piece of equipment.I would recommend flushing and draining tank once a year.Does the closed loop have glycol or an inhibitor added to the water in the system.The reason I ask is Runtals are made out of steel and will oxidize and can rust out .The ph of the water should be checked. I would leave your system alone but would add a thermostatic mixing valve to the domestic hot water to prevent being scalded.

Thanks guys!

The upper floor radiators where originally spec/designed for 120deg water - so I am glad to hear that running them a bit hotter doesn't pose any other problems for the slab zones.

Can someone explain to me in simple terms how the outdoor reset is installed (plus average cost) to an already setup system?

I don't know what is in the system as far as a inhibitor (I just did a air bleed on one Runtal and it certainly smelled like a little more than water). I have a PH tester in my wine making kit so I could test it...

I will look for a new friend in the industry - the pickings here are pretty poor it seems.

I would not bother with ODR after-the-fact. Be happy.

A well designed hydronic heating control system will continually adjust the heat delivery rate to match the actual heat loss of the building. For a given building construction, the heat loss of the building depends on the difference between the actual inside and outside temp. The objective is to maintain a constant comfort level (which is akin to maintaining a constant indoor temp) no matter the outdoor temp. So Outdoor Reset Control (ORC) simply uses the outside temp to determine the target water supply temp for the hydronic circuits in an attempt to accomplish this objective. The colder the outside temp, the hotter the supply temp... ORC is usually accomplished by the controller either resetting the boiler temp or resetting mixer valve temp(s) to achieve this target supply temp. ORC is a relatively crude controller approach now-a-days (because slab thermal inertia is not addressed), but it is certainly better (i.e., greater comfort level and less operating cost) than just operating at a fixed supply temp if your building is in a climate with significant daily temp swings. However, I agree with Badger that it is probably not worth chasing ORC now.

Once again - thank you everyone for the advice.

I will just work on keeping the systems running well over time.

We only need heat a few months a year - and our cold days are typically sunny anyway so the house will heat up via solar gain later in the day on its own. Oh yeah our cold days aren't really cold. I think we saw 31deg a few days ago and that will most likely be the coldest day of the year and it lasted for just a couple of hours.