Do I need to replace my fan coil?
If you still have your unit’s original fan coil (25+ years old), you’ll need to replace it very soon - certainly within the next five years; better yet, as soon as possible. There’s a danger that a leak will develop in the coil itself. (As of today, this has happened in approximately five units.) The potential for damage to the building may be great. It depends on where your coil is located and where the water goes when it spurts out of the coil.
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How should people maintain their fan coils?
This is documented on our Wiki: https://sites.google.com/site/cambridgecohousing/board/systems/hvac_1. The HVAC Circle will maintain the wiki pages with the latest information.
Who do I contact to get my fan coil replaced or repaired or serviced?
As of Sept, 2023, we recommend:
James Mcneil, Real Pro Mechanical, j_r_mcneil@hotmail.com, 857-544-2932.
John Cresta, JWC Plumbing and Heating, johncresta1@gmail.com, 339-226-0347.
Robin for many minor things - e.g. possible drain blockage
HVAC circle for triage and context.
What is the plan for whose fan coil gets replaced and when?
Unit Owners can replace their fan coils whenever they want to, using the vendor of their choice. However, we hope that most Unit Owners will be willing to use the community's approved vendors, and cooperate with the HVAC Circle to coordinate their fan coil replacement.
The HVAC Circle surveyed the community, so we think we know who is ready and willing to replace their fan coils in the near future. If you are ready and willing, but did not answer the survey, please send an email to let us know - cch-hvac@googlegroups.com. This will help us plan ahead and manage our preferred vendors' schedules.
The decision about which fan coils to install next will be made about 2-3 months out, based on a large variety of factors, including: need (is unit in imminent need of repair?); readiness and willingness of Unit Owners; availability of vendors; lead time and availability of equipment; time of year; and other technical factors.
It is your responsibility to contract with the vendor (which we hope will be one of our approved vendors). After that, a new fan coil may need to be ordered, or we may have an appropriate one available “in stock” that can be used (in which case, the Unit Owner is responsible for replacing it, and will be billed by CCH). Before the new fan coil can be installed, the Unit Owner needs to go over the design details with their chosen vendor. Each job will be different. Some jobs are going to be much harder than others depending on legacy issues around their design, installation and access. HVAC Circle members may be available for consultation. A design consultation with Randell (highly recommended) will be paid by CCH and billed back to the Unit Owner.
Our current guess is that most fan coil replacements will cost between $8-15k, assuming you use our approved vendors. This is a rough guess, based on previous replacements. A true cost estimate can only can only come from your chosen provider after they have reviewed the details of your particular situation.
(Bob Melvin)
During cold months, the heating season, a fan coil takes in hot water and produces warm air distributed to living spaces via air ducts and vents. It uses the hot water to heat up a panel of metal fins (similar to a car's radiator). Fans blow air across the hot fins producing warm air. The warm air blows into a box called a “supply plenum” where solid or flexible wall ducts deliver the air to the different rooms of a living space.
In the summer, the cooling season, the same equipment takes cold water and produces air conditioning. Air-conditioning is different from cooling in that cooling simply lowers the temperature of the air. Air conditioning performs the additional task of lowering the humidity of the air. A fan coil removes humidity when the water circulating through the fins is cold enough to produce condensation. The air temperature at which condensation forms is called the “dew point” and changes with the weather. Typically, the chilled water needs to be colder than 55°F to cause condensation and remove humidity from air passing through the fan coil.
A fan coil is one component of a larger heating and cooling system. A self-contained air conditioner or heat pump (uses the same equipment as an air conditioner to produce heat) has a small fan coil in it. systems that use a separate fan coil for distribution, have compressors and heat exchangers in a separate location. In our case, the compressors and heat exchangers are located in the mechanical room in the basement of the common house. The equipment in the mechanical room produces hot water during the heating season and cold water during the cooling season. Fan coil units are the same regardless of the source of the hot or cold water. The fact that Cambridge Cohousing produces hot and cold water for heating and air-conditioning using ground source heat pumps has no impact on the fan coil units located throughout the community. For more information on the ground source heat pumps please see the section of the handbook entitled “Ground Source Heat Pumps.”
(Bob Cowherd)
September and May: replace the filter
May: Blow out the condensate drain line; drop a fungicide tablet in the condensate drain pan; inspect system operation including: insulation, condensate overflow cutoff switch, pump and valves, and thermostat
May of presidential election/Olympics year: clean dust from coils and motor (some dis-assembly required). Note: There is nothing to lubricate on the fan motors.
(Bob Cowherd)
If you have a fan coil located in your ceiling, it's especially important to keep the drain line from your fan coil clear. If the lines become clogged, the drain pan will overflow onto the back of the ceiling and cause damage to your unit. When this happens, we need to use compressed air to unclog the drain line. Better to prevent clogging by doing regular preventative maintenance once a year, prior to the cooling season. This may involve blowing out the drain line with condensed air, and installing an antimicrobial tablet in the condensate drain pan. It only takes a few minutes.
Townhouses with basements have a "HomeRun" fan coil unit that drains condensate using a pump. Theoretically, it can also become clogged, though we have not seen any instances of this. More likely, the pump will fail. For this reason, we recommend installing a leak alarm near the base of the HomeRun fan coil unit (or inside the unit's galvanized metal stand).
What has done successfully for residents for years:
Remove cover of HVAC system (some screws may barely hold or be missing; the open cover can fall if you slide it horizontally)
Inspect for mold, noise, damage, excess condensation (insulate bare pipes)
Check water level in drain pan, and if over a quarter inch, check drain line as below
Put antimicrobial tablet in drain pan (2 if pan has spilled over in past), and close cover
Check drain line, and unclog with tablets (If pan has spilled over recently or is found partly filled):
Run cooling for 10 minutes to drip into pan
Remove drain hose from down pipe under nearby sink; keep bowl ready to catch flow
If a small steady stream runs out, it is ok, put 1 tablet in drain pan and finish
If steadily dripping, put 2 tablets in drain pan and finish
If barely or not dripping, blow out pipes as below
Blow out pipes, if needed:
From the compressed air can, insert its thin tube into a hole in a small cork
Insert the cork firmly into bottom of rubber hose under sink
Spread bowls and towels to catch falling splashes, and to protect nearby fire sensors, etc.
If only the lower drain pipe is clogged, insert firmly a cork in upper pipe, then trigger air can about 2 seconds until you hear splashing above
If both pipes are clogged, plug upper pipe and blow out lower, then plug lower and blow out upper
Put 2 tablets in drain pan and finish
How condensate is drained, or not:
Cold water in the system condenses water onto the cooling coil and its fins
Water drips into drain pan
2 pipes drain the pan, one flush with pan floor, one a little higher (saves you if lower one clogs
2 pipes run across ceiling to a black rubber hose down to a drain under a nearby sink
Algae, mold, fungus, and bacteria can grow and make films, eating dust in the condensate
A dirty air filter makes fan work harder, lowers air pressure in the system, and draws in more dust through any cracks, feeding bugs
For help with condensate drain maintenance, all Robin 617-876-7282
(Robin 2020, Edits by Bob M 2023)
Fan coil units should last several decades. However, certain types of premature failure may require an owner to replace the entire fan coil unit prior to the end of its normal service life. In addition, it may prove prudent in the long run to replace fan coil units when other significant work needs to be done. As of 2011, six fan coil units have been replaced in individual units. In the fall of 2008, the Managing Board adopted requirements for fan coil replacements in consultation with Gary Elovitz of Energy Economics of Newton Massachusetts, and The Hofeller Company. These guidelines are required for any future fan coil replacement. See the attached document below: FanCoilReplacementRequirements-CambCoho-EnergyEconomics-24Nov2008.pdf.
(Bob Cowherd)