FDQ250B noise level

[multisync]

We are about to put 4 x FDQ250B Daikin ducted (but with no ducting just blowing in free air or maybe a insulated plenum on the front ?) in a warehouse for heating and cooling.

The customer has now asked if they are noisy

Has anyone fitted any and can comment?

[VRVIII]

We are about to put 4 x FDQ250B Daikin ducted (but with no ducting just blowing in free air or maybe a insulated plenum on the front ?) in a warehouse for heating and cooling.

The customer has now asked if they are noisy

Has anyone fitted any and can comment?

Hi Multi,

The units are designed to overcome high static pressure of ductwork, 250Pa max with an air flow of 89m3/min. The noise level will increase with no ductwork due to the increased air velocity.
Would you not consider installing 2m of return ducting with filter access/box and 2m of discharge ducting with louvers to force air downwards.

[multisync]

Hi Multi,

The units are designed to overcome high static pressure of ductwork, 250Pa max with an air flow of 89m3/min. The noise level will increase with no ductwork due to the increased air velocity.
Would you not consider installing 2m of return ducting with filter access/box and 2m of discharge ducting with louvers to force air downwards.

We had considered installing silencers on the supply and return which would have the duel effect of noise reduction and increase static.

we also toyed with the idea of having the supply with a Tee and a damper which would deflect the air down in winter for heating and straight out for cooling.

They are to be installed in a warehouse at the top of the apex. We have done this a few times and found it to be very effective. Although that was using smaller 17kw units which have a lower air flow rate and plenum boxes on the front. I don't want to turn them on and have everyone dive for cover! I suppose we could make them twin splits with 2 x 12.5 kw which may be quieter..

Also I seem to remember there are 3 tappings for the fan speed. Is it low med and high and it's wired at med and high or is it low and med..?

Job starts v. soon and we're starting to get twitchy

[VRVIII]

Also I seem to remember there are 3 tappings for the fan speed. Is it low med and high and it's wired at med and high or is it low and med..?

Job starts v. soon and we're starting to get twitchy

FDQ250B only has high and med fan tappings The smaller units have 3 tappings.

[multisync]

FDQ250B only has high and med fan tappings The smaller units have 3 tappings.

Poo, best twin them up I guess..

[VRVIII]

Poo, best twin them up I guess..

If you use 2 x FBQ125C as twin system, these have inverter fan motors with a wide range of ESP adjustment and auto ESP adjust

[multisync]

If you use 2 x FBQ125C as twin system, these have inverter fan motors with a wide range of ESP adjustment and auto ESP adjust

That was our original plan but we were looking to save time and dare i say money. However we have to look the customer in the eye so if the 125's sense the lack of ducting and reduce fan speed then that's the best way for us to proceed. We fitted a 250 (or maybe a 200?) a few years ago and remember it as bloody noisy.

In this job With 4 suspended in free air and being adjacent to the mezzanine offices I don't think they'd be best pleased..

[VRVIII]

That was our original plan but we were looking to save time and dare i say money. However we have to look the customer in the eye so if the 125's sense the lack of ducting and reduce fan speed then that's the best way for us to proceed. We fitted a 250 (or maybe a 200?) a few years ago and remember it as bloody noisy.

In this job With 4 suspended in free air and being adjacent to the mezzanine offices I don't think they'd be best pleased..

I would still install discharge duct/plenum with louver to force hot air down and prevent any chance of recirc

[multisync]

I would still install discharge duct/plenum with louver to force hot air down and prevent any chance of recirc

There is no chance of recirculation.

With the units suspended just below the roof at the apex blowing across the air follows the roof line (coanda effect) to the wall and drops down and around.

This creates a really good airflow through the racking and back up. As I say we have done this in two other warehouses with full temperture monitoring (being drug storage it's mandatory) and they were happy to see less than 2 deg diff across the sensors scattered throughout the warehouse.