MasterTemp Pool and Spa Heater P/N 474131 Rev. M 8/2020
56
DE-LIMING THE HEATER
WARNING
Working with muriatic acid can be dangerous.
When cleaning elements always wear rubber gloves and eye
protection. Add acid to water, do not add water to acid. Splashing or spilling acid can cause severe personal injury
and/or property damage.
Should a heater require de-liming, this may be accomplished by circulating a solution of 30% Muriatic Acid. This process should
only be performed by a person of sufficient skill. The heater
MUST
be disconnected from the pool plumbing, gas plumbing, and
electric. The heater may be placed on its side with the water manifold “up”. The diluted muriatic acid may be recirculated until
visible bubbles are no longer produced. Before being restored to service, the heater water ways should be completely rinsed with
regular tap water.
PRESSURE RELIEF VALVE
Local codes may require installation of a pressure relief valve (PRV). Purchase separately
and install a 19 mm pressure relief
valve complying with the local Plumbing Codes, having a capacity equal to the Mega Joule (MJ/hr) rating of the heater. The
relief pressure of the valve MUST NOT EXCEED 344 kPa. The relief valve must be installed vertically. To install the valve, use a
19 mm x 5 mm brass nipple at the manifold, the two brass elbows and nipples are (user supplied), as illustrated in
Figure 45. No valve
is allowed to be placed between the manifold adapter and the relief valve. To avoid water damage or scalding from operation of
the relief valve, install a drain pipe in the outlet of the pressure relief valve that will direct water discharging from the valve to a
safe place for disposal. Do not install any reducing couplings or valves in the drain pipe. The drain pipe must be installed so as
to allow complete drainage from the valve and drain line.
The relief valve should be tested at least once a year by lifting
the valve lever.
WARNING
Explosion hazard.
Any heater installed with restrictive devices in the piping system downstream from the heater, (including
check valves, isolation valves, flow nozzles, or therapeutic pool valving), must have a relief valve installed as described above.
Section 4. Maintenance
Figure 46.
Drill through the NPT Port, then
use a 3/4" x 2.50 (2.0 cm x 6.35 cm)
Brass Nipple and Elbow
(user supplied) for a PRV Installation
3/4” x 2.0” Brass Nipple
(2.0 cm x 5.08 cm)
PRV
3/4” x 3.5” Brass Nipple
(2.0 cm x 8.89 cm)
