Bosch AQ4 Installation Manual Download Page 8

8

AQ4 Manual

Fig. 8 Water valve pin

Water valve pin

AQ4 Installation instructions

2.7 Flow switch

Replacement piping and flow switch is included for 

1600P/425PN  and  1600H/425HN  water  heaters. 

Check your model number on the right side of the 

water heater cover to confirm which procedure to 

follow.
2.7.1 Models 1600P/425PN
1.  Shut  off  cold  water  supply  isolation  valve.    If 

none installed, install before proceeding. Open 

hot water tap to relieve water pressure if water 

is already connected. 

2.  Remove and save clip on lower right side of heat 

exchanger.

3.  Using a flat head screw driver remove and save 

pin from front, right side of water valve. (Fig. 8)

4.  Remove copper pipe and set aside.

5.  Find  and  connect  the  black  flow  switch  to  the 

bushing  and  pipes  shown  in  Fig.  9A.    Secure 

together with supplied clips.

6.  Position  flow  switch  and  connecting  pipe  and 

bushing  in  place  of  the  copper  pipe  that  was 

removed.

7.  Reinstall  pin  in  water  valve  and  clip  on  heat 

exchanger connection.

8.  Connnect the three prong Molex connector cable 

to the flow switch.

9.  Connect control cable from vent motor to Molex 

connector cable with wire nuts as seen in 

     Fig. 10.
2.7.2 Models 1600H/425HN
1.  Shut  off  cold  water  supply  isolation  valve.    If 

none installed, install before proceeding. Open 

hot water tap to relieve water pressure if water 

is already connected. 

2.  Remove  and  save  clip  on  lower  right  side  of 

hydrogenerator.

3.  Remove  and  save  pin  from  front,  right  side  of 

water valve using a flat head screwdriver. 

    (Fig. 8)

4.  Remove copper pipe and set aside.

5.  Find  and  connect  the  black  flow  switch  to  the 

pipes shown in Fig. 9B. 

Note:

 

There are two pipes included for connection 

from  flow  switch  to  hydro-generator.    One  is 

slightly  longer  than  the  other.    If  your  water 

heater’s serial number is greater than FD792, you 
must use the longer pipe for this connection.

6.  Position flow switch and connecting pipes in place 

of  the  copper  pipe  that  was  removed.  Secure 

together with supplied clips.

7.  Reinstall  pin  in  water  valve  and  clip  on  heat 

exchanger.

8.  Connnect the three prong Molex connector cable 

to the flow switch.

9.  Connect control cable to Molex connector cable 

with wire nuts as seen in Fig. 10.

Fig. 10 Flow switch electrical connections

Connections from 

Molex connector 

cable (white and 

yellow)

Connection from 

vent motor (black 

and red)

Fig. 9B 1600H/425HN flow switch connections

Connection to 

water valve

Connection to 

hydro generator

Flow switch 

molex connector 

Fig. 9A 1600P/425PN flow switch connections

Brass heat 

exchanger 

bushing

Connection to 

water valve

Flow switch 

molex connector 

Replacement 

pipe for pilot 

models

Replacement 

pipes for hydro 

models

Pipe to heat 

exchanger

Summary of Contents for AQ4

Page 1: ...iance Improper installation adjustment alteration service or maintenance can cause injury or property damage Refer to this manual For assistance or additional information consult a qualified installer service agency or the gas supplier In the Commonwealth of Massachusetts this product must be installed by a licensed plumber or gas fitter Upon completion of the installation these instructions shoul...

Page 2: ...Vent piping 7 2 6 Linear safety spillage switch 7 2 7 Flow switch 8 3 Operation 9 3 1 First time start up 9 4 Maintenance 10 5 Troubleshooting 10 5 1 Introduction 10 5 2 Power vent motor runs all the time or intermittently without water flow 10 5 3 Pilot will not hold when lit or spark automatically with hot water flow 11 5 4 Sparks but pilot will not light 5 5 Pilot goes out during hot water use ...

Page 3: ...The power vent motor shaft must be mounted horizontally to prevent motor bearing wear 4 Disconnect power supply when making wiring connections or when working around the fan blade and motor Failure to do so may result in severe personal injury and equipment damage 5 Make certain the power source is adequate for the fan motor requirements Do not add the power vent to a circuit where the total load ...

Page 4: ...g at a minimum height of eight 8 feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment The sign shall read in print size no less than one half 1 2 inch in size GAS VENT DIRECTLY BELOW KEEP CLEAR OF ALL OBSTRUCTIONS 4 INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled equipment ...

Page 5: ...en located adjacent to a public walkway The venting system shall terminate at least 3 feet above any forced air inlet within 10 feet The venting system shall terminate at least 4 feet below 4 feet horizontally from or 1 foot above any door window or gravity air inlet into any building 2 3 Power vent hood 1 Attach the mounting template on page 14 to the interior wall that the vent hood will be pene...

Page 6: ...r sleeve of the vent hood Fig 4 Use the four pre punched holes in the outlet collar of the power vent motor as a guide to drill diameter holes into the vent pipe Fasten power vent motor outlet to the vent hood inlet using sheet metal screws Seal the connection with high temperature silicone sealant Note Any additional vent pipe used between the power vent motor and the vent hood will be under posi...

Page 7: ... the draft spillage sensing switch will open the pilot safety circuit and shut off all gas to the water heater The switch is normally closed and opens at temperatures greater than 185º F It has a manual reset button Mounting the linear safety spillage switch 1 Attach the spillage switch to the top left of the heater s draft diverter using the existing hole and the included mounting screw Fig 6 2 L...

Page 8: ...lled install before proceeding Open hot water tap to relieve water pressure if water is already connected 2 Remove and save clip on lower right side of hydrogenerator 3 Remove and save pin from front right side of water valve using a flat head screwdriver Fig 8 4 Remove copper pipe and set aside 5 Find and connect the black flow switch to the pipes shown in Fig 9B Note There are two pipes included...

Page 9: ...structions in water heater installation manual 3 1 3 Draft test 1 Operate the water heater by running hot water Check for proper combustion and ensure there is no spillage by holding an recently extinguished match or other visible smoke source in front of the draft divertor The smoke from the extinguished match should be quickly sucked into the opening and up the exhaust venting If the smoke is bl...

Page 10: ... 1 The power vent motor is flow switch activated If the internal paddle inside the flow switch is jammed it may constantly send a signal to turn on the fan Shut off water supply to heater and drain Remove flow switch from water heater piping by removing clips on both ends Flush water through both ends of flow switch to free up internal paddle and clear debris After flushing shake flow switch up an...

Page 11: ...ut during hot water use 1 Inspect entire vent system for blockage or obstruction Ensure the back draft flapper installed on the power vent hood swings freely 2 Verify power vent fan operates with water flow If not verify wire connection from flow switch to fan motor Clean cold water inlet filter and verify flow rate through the water heater is adequate enough to activate the flow switch If flow ra...

Page 12: ...ranty does not cover any labor costs associated with service removal or re installation of part s All such costs must be borne by the Purchaser Additionally this warranty does not cover any labor costs associated with service removal or re installation of the original vent kit or a replaced vent kit How to Make a Claim Any claim for warranty parts should be made to your local dealer distributor or...

Page 13: ...VDC RED 115VAC BLACK BLACK BLACK BLACK WHITE WHITE WHITE GREEN GREEN 115 1 60 PLUG TIMER RELAY POWER VENT MOTOR YELLOW WIRE NUT WIRE NUT C NO NC YELLOW RED TIMER RELAY 2 1 BLUE Wiring Diagram 7 Wiring diagram Fig 12 Fan wiring diagram Fig 13 Safety circuit wiring diagram 425HN and 1600H wiring 425PN and 1600P wiring ...

Page 14: ...l the vent hood will be penetrating 2 Verify that wall penetration will not come in contact with concealed wiring or plumbing Using a 1 2 drill bit drill two pilot holes where noted on the template The drill bit must be long enough to penetrate to the building exterior 3 Attach the template to the building exterior aligning the pilot holes on the template with the pilot holes drilled in step 2 4 U...

Page 15: ...15 AQ4 Manual Notes ...

Page 16: ...BTC 718003301 C Bosch Thermotechnology Corp 50 Wentworth Avenue Londonderry NH 03053 Tel 1 866 642 3198 Fax 1 603 584 1681 www bosch climate us ...

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