Warranties

The Company has warranties with various terms ranging from 18 months for parts to 25 years for certain heat exchangers. The Company has an obligation to replace parts or service its products if conditions under the warranty are met. A provision is made for estimated warranty costs at the time the related products are sold based upon the warranty period, historical trends, new products and any known identifiable warranty issues.

Changes in the warranty accrual are as follows:



	Three months ended						Nine months ended
	September 30, 2018			September 30, 2017			September 30, 2018			September 30, 2017
Warranty accrual:	(in thousands)
Balance, beginning of period	$	11,458		$	8,602		$	10,483		$	7,936
Payments made	(2,355		)	(2,281		)	(6,078		)	(5,935		)
Provisions	3,050			3,277			7,748			7,597
Balance, end of period	$	12,153		$	9,598		$	12,153		$	9,598

Warranty expense:	$	3,050		$	3,277		$	7,748		$	7,597