Heating, Air Conditioning, Fridge, HVAC/3rd Zone Baseboard Heat addition


Boiler Spece
Boiler Spece  
Dear Craig,

My house was flooded in Superstorm Sandy in New Jersey.  As a result the Circulating hot water boiler was replaced within the first 2 weeks with a new equivalent Weil McLain CGI-6 Pin unit.  Pre-Sandy, the 2 story ∼ 3000 square foot baseboard heated house contained 3 solenoid valve / 3 thermostat controlled zones with 2 pumps.  One pump operates through 2 zones / 2 thermostats for the 1st and 2nd stories.  Another pump operates through the radiant floor heat zone / 1 thermostat under the entrance foyer, kitchen and dining area floors, roughly 50% of the footprint of the 1st floor.  All zones operated through the coldest of climates in the NJ winter with sufficient capacity to meet the thermostat demand.  After re-building the first floor post Sandy, it was discovered that there was a lot of damage and a lot of cost associated with replacing the radiant floor heat zone.  We opted to place a few more sections of baseboard heaters and R-30 batt insulation in the crawl space beneath the 1st floor and not endure the cost of re-installing the expensive radiant floor heat.  The next winter came and went the heat seemed somewhat adequate with the exception of a handful of the coldest days in the extreme winter where the 1st floor thermostat lagged the demand by a few degrees during the coldest nights.  The 2nd floor was not changed in any way and the thermostat demand is always met.  We have just recently lifted our house 5 onto the existing block foundation for future storm mitigation purposes.  This combined with FEMA required flood vents added significant air volume and colder temperature to the underside of the house.  The previous crawlspace was approximately 3 feet with about 2 feet sub-grade and only contained 3 fixed flood vents.  The present crawl space is ∼ 8 feet high with 3 sides only 2 feet sub-grade, and one side level with the outside grade as it was re-graded by code to allow ebb and flow of any future storm water entrance.  There are also now installed 7 FEMA approved Smart Flood Vents that are within 1-foot of grade, 2 added windows and an entrance door.  The additional volume above grade combined with the windows, flood vents and door, now allow colder air too enter beneath the 1st floor.  This winter has only seen a few days under 30 degrees, but the 1st floor thermostat demand and actual temperature on the 1st floor are now grossly behind, only reaching into the low 60s.  I added foam insulation to all 1st floor zone piping that traverses the crawlspace.  I still have as yet have finished adding a 4 inch layer of concrete to the new crawlspace floor.  The square footage of the crawl space is 27 x 50.  My idea was to run some Pex tubing prior to the pouring of the concrete and add / replace the 3rd zone with a radiant heat floor in the crawlspace to maintain this area at approximately 50 degrees, so the 1st floor heat could keep up with demand during the coldest of winter days.  I am looking to see 1) if this is possible and 2) how far apart or how do I run or how do I calculate such, the Pex tubing or equivalent to achieve this while not exceeding the capabilities of the mentioned boiler.  Any assistance on this situation would be much appreciated.  Any further information that you need, please feel free to ask.

Thanks in advance,

Unless the gas is free, heating the crawl space is not something I would suggest.   It is likely the boiler you have just will not keep up with demand.  You should concentrate your efforts on insulating the home and installing vapor barriers.  I do not know anything about flood vents, but it would seem to me there is a way to stop cold air from getting through them.  You should keep the cold out rather then heating unused space.  You should also check the water temp set point for the boiler.  It might be possible the temp is just not set high enough.  

It is hard for me to sit here staring at a computer screen to be of  much help otherwise.


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Craig HVAC Expert


I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.


I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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