Raypak MVB 5042004 User Manual

Page 17

The MVB must be equipped with a field-supplied ex-

ternal pump and bypass arrangement. This

arrangement blends outlet water with the inlet water to

increase the inlet water temperature to a minimum of

105°F (40°C) for Pool Heater (P and WHP) versions

and 120°F (49°C) for Hydronic Heating (H7) or

Domestic Hot Water (WH1) versions, thereby reducing

the likelihood of condensation forming on the heat

exchanger. The pump also serves to circulate water

through the heater from the main system piping.

To complete the installation of the pool heater, the pool

thermostat must be installed in the main return water

line, upstream of the heater. This will ensure that the

heater will be energized at the right time.

Adjustment of the manual bypass valve is critical to

proper operation of the heater. The manual bypass

valve should be adjusted to achieve a minimum inlet

water temperature of 105°F (40°C) for Pool Heater (P

and WHP) versions and 120°F (49°C) for Hydronic

Heating (H7) or Domestic Hot Water (WH1) versions

and a system supply water temperature below 140°F

(60°C). When starting with a cold pool, make initial

adjustments. Make final adjustments when pool water

approaches desired temperature.

The use of a bypass is required for proper operation in

a pool heating application. Use the following instruc-

tions to set the manual bypass:

CAUTION: Power to the heater should be

interlocked with the main system pump to make sure

the heater does not fire without the main system

pump in operation. Improper flow control can

damage the heater. Uncontrolled flow (too high) or

restricted flow (too low) can seriously damage the

heater. Follow these instructions to make sure your

heater is properly installed.

1. Turn on pump.

2. Turn on heater and wait until heater goes to full

fire.

3. With the heater operating at 100% firing rate, set

Valve A (the bypass) to

⁄

open position, and Valve

B to fully open position. See Fig. 16.

4. Adjust Valve A until the inlet water temperature is

105°F (40°C) or 120°F (49°C) depending upon

heater type.

5. If this process does not raise the inlet water tem-

perature to 105°F (40°C) for Pool Heater (P and

WHP) versions and 120°F (49°C) for Hydronic

Heating (H7) or Domestic Hot Water (WH1) ver-

sions and Valve A is fully open, then slowly throttle

Valve B closed to increase the inlet water temper-

ature to the required temperature.

POOL

THERMOSTAT

FROM

FILTER

TO POOL

CHEMICAL

FEED

Fig. 15: Single Pool Heater Application

NOTE: Opening the valve will increase the

temperature and closing the valve will decrease the

temperature.

*Maximum 4 times the pipe diameter or 12”, whichever is less.

Fig. 16: “H” Bypass Setting