Carrier 28QX - Manual (Page 24)

19. This will prevent booster pump from filling
storage tank. Open air bleed valve on top of 28QX
coil, start pump and fill piping loop with water.
If 28QX is not at highest point in the water
loop, install an air bleed valve at high point in loop
to purge air. After loop is filled, remove booster
pump and open ball valve in pump package.
CONTROL ADJUSTMENTS ^ The aquastat with
the adjustment knob on the side of the control box
must be set. It must be set to the value that is
specified by the Solar Clic Program. Room ther­
mostat adjustment is same as in 38HQ Heat Pump
Installation Booklet.
Glycol System Start-Up — At this point, all
components should be in place and all piping and
electrical connections should be made. The storage
tank should not yet be insulated, and the fused
disconnect should be off. Begin filling the storage
tank as is described in the “Plain Water System
Start-Up” under “Collector Loop.” Check the tank
for leaks, especially at the tank fittings and add the
inhibitor, pg 25.
SOLAR COLLECTOR PIPING LOOP - If the
34GL257 or 34GL367 has been installed, the
collector pump must be oiled with the factory
supplied tube of oil. Follow the oiling instructions
on the oil tube and the oil warning tag. If the
34GL257 has been installed, remove the shipping
bracket from the collector pump.
The expansion tank (Fig. 12 and 19) in the
collector loop will require the addition of a
glycol-water mixture. Standard automotive anti­
freeze (Dow, Prestone, Peak, etc.) will be used as
the glycol source. Determine what percentage of
glycol is proper for the particular application using
the glycol manufacturer’s data. Use the glycol
charging chart to determine the total amount of
glycol-water mixture required. Add the required
amount to the expansion tank using the hole in the
top of the tank and a funnel as entry into the tank
(Fig. 29). If the glycol charging chart requires more
than 18 gal. (the capacity of the expansion tank),
add as much as possible and save the remainder to
be added after the collector pump is operating.
Bleed the air out of the collector pump (34GL257
and 34GL367 only) as described in the “Collector
Loop” section of the “Plain Water System
Start-Up” procedure.
Before starting collector pump locate sight glass
at bottom of expansion tank (Fig. 29). The sight
glass is for checking glycol level in tank when
collector pump is operating. If glycol level falls
below the sight glass, collector pump inlet takes in
air and pump won’t function properly. If complete
glycol-water charge was not all added initially, it
can be added when collector pump is started and
space in expansion tank becomes available.
Switch on fused disconnect to energize col­
lector pump. (Follow procedure outlined in the
“Collector Loop” section of the “Plain Water
System Start-Up” instructions.) Determine that
collector piping loop is leak tight and then shut off
collector pump. After shutdown, look thru hole in
top of expansion tank to be sure the glycol drains
back.
Fig. 29 — Filling Expansion Tank
Table 4 — Glycol Charging Chart
Lineal Ft of Piping
from Collector Pump
to Collectors
TOTAL NO. OF COLLECTORS
15 10 20
.1.
25
Glycol/Water Mixture (Gal.)
10 11 13 15 17
20 13 14 16 18
30 14 16 ,,,
: 19
40 15 17 J 19 20
50 16 .18 1 20 22
60 „JS... 5 "l9 21 23
When glycol/water charge is over 18 gal., the remainder
must be added after collector pump is operating
TRI-X COIL LOOP - Follow the procedure
outlined in the “Tri-X Loop” section of the “Plain
Water System Start-Up” instructions.
HEAT EXCHANGER LOOP - Since the heat
exchanger pump is electrically parallel to the
collector pump, it has already run. However, if the
heat exchanger loop is a closed one, bleed the air
out of the loop. If the loop is an open one (the
return pipe is not below the water’s lowest level in
storage tank), the bleed procedure does not have to
be followed. To bleed the closed loop, loosen the
bleed screw at the top of the heat exchanger as
shown in Fig. 30.
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