HS Tarm 2000, Installation And Operation Manual

Page: 24 / 66

I
NSTALLATION (continued)
PAGE 20
__________________________________________________________________________________________________________________________________________________________________________________
Installation of Domestic Hot Water Coil
A tankless coil for heating domestic hot water is available as a factory installed option with the
Tarm EXCEL boilers, or it may easily be added after the boiler is already installed. For ready
access to the coil, the cover plate on the jacket is removable.
NOTE: In certain areas, existing water supplies may have a high mineral content. This will
lead to liming of the coil over time, depending on the mineral content of the water,
the amount of water passing through the coil, and the boiler temperature. If the
boiler temperature can be kept under 160
°
F the buildup in the coils will be much
less. Coils should be cleaned as soon as there is any indication that the hot water
supply is being restricted. Coils are cleaned with hydrochloric acid--
CLEANING
THE COIL IS A DANGEROUS PROCEDURE THAT SHOULD BE ATTEMPTED
ONLY BY A QUALIFIED AND EXPERIENCED TECHNICIAN.
1. Pipe the cold water to tapping #12, and hot water from tapping #13 (or vice versa). It is
desirable to install unions external to the boiler in both the cold and hot water lines.
NOTE: If a separate hot water heater will be used to heat domestic water during the
warmer months, cold water must be piped separately to the separate water heater,
not through the coil in the TARM boiler.
COLD WATER MUST NOT FLOW
THROUGH THE TARM DOMESTIC COIL IF THE TARM BOILER IS UNHEATED!
CONDENSATION AND CORROSION OF THE BOILER BODY CAN RESULT IF
WATER FLOWS THROUGH THE COIL OF AN UNHEATED BOILER
.
2. Install the Coil Pressure Relief Valve (#17-402-02, 100PSI) in a tee on the cold water
supply to the tankless coil with the relief valve mounted vertically. There must be no
shut-off valve or check valve between the coil relief valve and the tankless coil.
WARNING: The Coil Relief Valve discharge line MUST BE PIPED TO WITHIN 6” OF THE
FLOOR NEAR A DRAIN AND MUST BE 3/4” PIPE WITH NO REDUCTION.
If this valve operates, hot water will be discharged. It should be piped to an
open drain so that this water will not damage the room in which the boiler is
located.
3. Install a tempering valve (Watts model #70A, or equivalent) and an anti-scald device in
the domestic hot water line out from the coil.
WARNING: A TEMPERING VALVE MUST BE INSTALLED TO PROTECT AGAINST
DANGEROUSLY HIGH DOMESTIC WATER TEMPERATURES AND TO
PREVENT THE POSSIBILITY OF A PERSON SUSTAINING SERIOUS
BURNS FROM DOMESTIC HOT WATER.
20